JP6293332B1 - Torque limiter - Google Patents

Abstract

Provided is a torque limiter that can transmit a large torque while having a small and compact structure, has a sufficiently small rotational play between an input member and an output member, and does not cause stress concentration between the two. thing. A conical surface is formed on the inner periphery of the outer ring, and an opposing conical surface is formed on the outer periphery of the inner ring to contact and press the conical surface in the axial direction. One of the ring 3 and the inner ring 4 is engaged with the inner ring 2 and the other is engaged with the housing 1 so as not to be relatively rotatable. Then, at least one of the outer ring 3 and the inner ring 4 is engaged with the other party by the involute spline so as not to be relatively rotatable. [Selection] Figure 1

Description

  The present invention includes a shaft-shaped inner ring and a housing that constitute an input member and an output member of a rotation transmission device, and when a rotational torque of a predetermined value or more acts between the inner ring and the housing, both rotate relatively. The present invention relates to a torque limiter.

  In recent years, daily necessities that automatically operate various components with a motor, for example, toilets that automatically open and close toilet seats and toilet lids are widely used. In such toilets, the toilet seat and toilet lid are normally opened and closed by motor drive, but the toilet seat and toilet lid may be opened and closed by an external force by a human hand or the like during the opening and closing operation. . In this case, since the motor is overloaded, in order to avoid this, a drive device that drives the toilet seat and the toilet lid is usually equipped with a torque limiter.

  As an example of a drive device for automatically opening and closing a toilet seat and a toilet lid, FIG. 13 shows a device disclosed in Patent Document 1, and FIG. 14 shows a single view of a torque limiter mounted on this drive device. The driving device DS includes a motor M as a driving source, a driven gear body JB for opening and closing a toilet seat and a toilet lid, which are driven devices, and a torque limiter TL provided between the motor M and the driven gear body JB. Composed.

The torque limiter TL includes a shaft member SM serving as a rotation center, an input member IM that is inserted through the shaft member SM and is provided coaxially therewith, an output member OM, a friction member FM, and an axial spring force applying member AM. . The input member IM is fixed to the shaft member SM, and includes a disk-shaped portion and an input cylindrical wall IC extending from the outer peripheral edge to one side in the axial direction. An input gear IG that receives rotational driving from the motor M is formed on the outer periphery of the input cylindrical wall IC. The output member OM is rotatable with respect to the shaft member SM, and includes a disk-shaped portion and an output cylindrical wall OC extending in one axial direction toward the opposite direction to the input member IM at the center thereof. . An output gear OG connected to the driven gear body JB is formed on the outer periphery of the output cylindrical wall OC.
The friction member FM is disposed in an annular space defined inside the input cylindrical wall IC, and includes a plurality of input plates IP and output plates OP each having an annular shape. The input plate IP and the output plate OP are alternately stacked in the axial direction, and these are engaged with the input member IM and the output member OM so as not to rotate relative to each other by fitting the grooves and the protrusions. The axial spring force applying member AM includes a disc-shaped washer W that contacts the output member OM, a coil spring SP that applies an axial spring force to the washer W, and a nut that adjusts the spring force of the coil spring SP. N. When the output member OM is pressed in the axial direction by the washer W, a predetermined frictional force is generated between the input plate IP and the output plate OP.

In a normal case, that is, when the toilet seat and toilet lid are opened and closed by a motor drive with a rotation torque of a predetermined value or less, the input member IM is rotated by the rotation drive transmitted from the motor M and the input member IM is rotated. The input plate IP, which is impossiblely engaged, rotates. At this time, since the input plate IP is connected to the output plate OP by a predetermined frictional force, the output plate OP and the output member OM that is non-rotatably engaged with the output plate OP rotate together. Therefore, the driven gear body JB connected to the output member OM also rotates together with the input member IM, and the toilet seat and toilet lid connected to the driven gear body JB automatically open and close.
On the other hand, when an external force greater than a predetermined rotational torque is applied while the toilet seat and toilet lid are driven by a motor, and the toilet seat and toilet lid are opened and closed by this, the rotational torque generated by the external force is driven by the driven gear body. It is transmitted to the output member OM via JB, overcomes the frictional force between the output plate OP and the input plate IP, the output plate OP slides with respect to the input plate IP, and between the output plate OP and the input plate IP. Slip occurs. Therefore, it is possible to avoid an external force exceeding a predetermined rotational torque, that is, an overload, from being applied to the motor.

Japanese Patent Laying-Open No. 2006-151297

  However, in the torque limiter described above, the axial spring force applying member AM that applies a pressing force in the axial direction to the friction member FM and generates a predetermined friction force on the axial direction is provided on the side opposite to the output member OM in the axial direction. Therefore, the entire apparatus cannot be made compact. Therefore, in the torque limiter described above, it cannot be installed in a small space such as a hinge portion that opens and closes a lid of a personal computer with a drive motor.

  In order to solve the above-mentioned problems, the present applicant uses a spring having a very large spring constant, such as a so-called ring spring, to increase the frictional force in a compact and compact structure prior to the filing of the present application. In addition, torque limiters in which the set value of the rotational torque is increased have been proposed (Japanese Patent Application Nos. 2006-17110 and 2006-17111). In these torque limiters, an outer ring and an inner ring having a conical surface and an opposing conical surface that are in contact with each other are used, and the outer ring and the inner ring are an inner ring or a housing that constitutes an input member and an output member of the rotation transmission device. Are engaged with each other so as not to be relatively rotatable. And when the rotational torque which acts between an outer ring and an inner ring exceeds the frictional force which acts between a conical surface and an opposing conical surface, both rings will start to rotate relatively.

Here, in the torque limiter proposed by the present applicant, in order to engage the outer ring and the inner ring in a relatively non-rotatable manner, a groove having a square cross section is provided in these rings, and the inner ring or the housing which is the counterpart, The cross section closely fitting with the square groove forms a square protrusion. Although such an engagement method is simple, it has been found that there is still room for improvement in the following points.
First, in order to bring the grooves and protrusions of the square cross section into close contact with each other, it is necessary to reduce the surface roughness of the contact surface, and it is difficult to process such grooves and protrusions with high accuracy. When the dimensional accuracy of the grooves and protrusions in the square cross section is reduced, so-called rotation play occurs between the inner ring and the housing constituting the input member and output member, and the torque limiter is installed in the rotation transmission system. When the input member is reversed, the output member is not immediately reversed, which causes an undesirable phenomenon as a rotation transmission device.
Second, when the rotational torque of the inner ring that is the input member is transmitted to the housing that is the output member via the grooves and protrusions having the square cross section, the stress tends to concentrate on the corners of the square cross section. The torque limiter proposed by the present applicant is compact and capable of transmitting high torque, but when shocking rotational torque is applied repeatedly, it is caused by stress concentration due to an increase in the surface pressure of the contact surface of the square cross section. Thus, cracks may occur in the grooves and protrusions having a square cross section.

  An object of the present invention is to solve the above-described problems in a torque limiter using a ring spring proposed by the present applicant.

In view of the above problems, the present invention provides a torque limiter that uses a ring spring principle to generate a large frictional force using an outer ring and an inner ring formed with a conical surface and an opposing conical surface that are in contact with each other. The ring and the inner ring are engaged with the inner ring or the housing by an involute spline so as not to rotate relative to each other. That is, the present invention
“A torque limiter comprising a shaft-shaped inner ring and a housing, and when a rotational torque of a predetermined value or more is applied between the inner ring and the housing, both of them rotate relatively,
An outer ring and an inner ring disposed adjacent to each other surrounding the inner ring are installed in the housing to have a common central axis;
A conical surface is formed on the inner periphery of the outer ring, and an opposing conical surface that is in contact with the conical surface and presses in the axial direction is formed on the outer periphery of the inner ring. One of the rings is engaged with the inner ring and the other is engaged with the housing in a relatively non-rotatable manner,
When a rotational torque of a predetermined value or more is applied between the inner ring and the housing, the inner ring and the inner ring against the frictional force between the conical surface of the outer ring and the opposing conical surface of the inner ring. The housing is configured to rotate relative to the housing; and
At least one of the outer ring and the inner ring is engaged with the other side by an involute spline so as not to be relatively rotatable.
The torque limiter is characterized by this.

The tooth shapes of the external teeth and the internal teeth constituting the involute spline can be set to have different dislocation amounts.
The housing is provided with the outer ring and the inner ring, and has a receiving space in which an opening is provided at an end portion in the axial direction, and the opening has a conical shape of the outer ring while shielding the opening. It is preferable that a lid member is provided for pressing the surface and the opposing conical surface of the inner ring in the axial direction.
It is preferable that external teeth are formed on the outer circumference of the inner ring and the housing over the entire length in the axial direction.
Both the outer ring and the inner ring can be formed of a plate-shaped metal including a flat portion and a conical portion connected thereto.

In the torque limiter of the present invention, the shaft-shaped inner ring, and the outer ring and the inner ring that surround the inner ring and are arranged adjacent to each other are installed in the housing so as to have a common central axis. One of the ring and the inner ring is engaged with the inner ring, and the other is engaged with the housing in a relatively non-rotatable manner. The outer ring and the inner ring are formed with a conical surface and an opposing conical surface that generate a frictional force due to an axial load, and if the rotational torque acting between the inner ring and the housing becomes larger than this frictional force, Rotate relatively.
As described above, the torque limiter according to the present invention generates a large frictional force by utilizing the principle of the ring spring, so that a large torque can be transmitted between the inner ring and the housing even if it is small. For example, in various power transmission systems, the space required for the torque limiter for protecting the drive motor can be reduced.

  In the torque limiter according to the present invention, at least one of the outer ring and the inner ring is engaged with the other party (inner ring or housing) by the involute spline so as not to be relatively rotatable. The involute spline is a fitting method in which a large number of involute-shaped external teeth and internal teeth are fitted and engaged, and the transmission torque between the inner ring and the housing is distributed over a large number of teeth. The force acting on the teeth will be small. Furthermore, since the contact portion between the inner tooth and the outer tooth becomes an involute curved surface, there is no portion that causes a sudden cross-sectional change, such as a corner, that occurs when the square groove and the protrusion are fitted together. It is possible to prevent the occurrence of cracks.

  Further, the external teeth and the internal teeth constituting the involute spline are the tooth profile of the involute gear that is commonly used as a rotation transmission component. A processing machine for processing such gears with high accuracy is also always provided in factories and the like, and the involute spline portion of the present invention can be easily formed with high accuracy using such a processing machine. Therefore, when comparing the engagement means that engages with the protrusion having a square cross section and the groove, the manufacturing cost is low, and the rotation play can be reduced by high-precision processing of the engagement portion.

It is a figure which shows the whole structure of 1st Example of the torque limiter of this invention. It is a figure which shows the housing of the torque limiter shown in FIG. It is a figure which shows the shield of the torque limiter shown in FIG. It is a figure which shows the inner ring | wheel of the torque limiter shown in FIG. It is a figure which shows the outer side ring of the torque limiter shown in FIG. It is a figure which shows the inner side ring of the torque limiter shown in FIG. It is a figure which shows the whole structure of 2nd Example of the torque limiter of this invention. It is a figure which shows the housing of the torque limiter shown in FIG. It is a figure which shows the shield of the torque limiter shown in FIG. It is a figure which shows the inner ring | wheel of the torque limiter shown in FIG. It is a figure which shows the outer side ring of the torque limiter shown in FIG. It is a figure which shows the inner side ring of the torque limiter shown in FIG. It is a figure which shows an example of the drive device used for an automatic opening / closing toilet seat and a toilet lid. It is a figure which shows the torque limiter of the drive device shown in FIG.

  Hereinafter, the torque limiter of the present invention will be described with reference to the drawings. FIG. 1 shows an overall structural diagram of a first embodiment of a torque limiter according to the present invention, and FIGS. 2 to 6 show single components of the components.

  As shown in FIG. 1, the torque limiter according to the first embodiment of the present invention includes a housing 1 having a gear shape with outer teeth 1H6 formed on the outer periphery, and the housing 1 has a common central shaft. An inner ring 2 having an o, an outer ring 3 and an inner ring 4 are provided.

Referring to FIGS. 2 and 3 together with FIG. 1, the housing 1 has a main body 1H and a lid member 1S. The main body 1H has a cylindrical shape as a whole. An end plate 1H1 is formed on one side in the axial direction, a circular opening 1H2 is provided on the other side in the axial direction, and an accommodation space 1H3 is formed inside. Yes. A circular hole 1H4 is provided in the center of the end plate 1H1. A plurality (six in this embodiment) of screw holes 1H5 are formed on the outer peripheral edge of the main body 1H at equal angular intervals in the circumferential direction. Each screw hole 1H5 penetrates in the axial direction, and the other side in the axial direction faces the opening 1H2.
Outer teeth 1H6 are formed on the outer circumference of the main body 1H over the entire length in the axial direction, and inner teeth 1H7 are formed on the outer circumference of the housing space 1H3. The external tooth 1H6 is a general gear for driving the driven device, while the internal tooth 1H7 forms the internal tooth side of the involute spline as will be described later. The tooth shapes of the external teeth 1H6 and the internal teeth 1H7 are both involute, the external teeth 1H6 have 43 teeth, and the internal teeth 1H7 have 24 teeth (the teeth are provided at the angular positions where the screw holes 1H5 are provided). Not)).
As clearly understood by referring to FIG. 3, the lid member 1 </ b> S is an annular plate member, and a small hole 1 </ b> S <b> 1 is provided at a position corresponding to the screw hole 1 </ b> H <b> 5 provided in the main body 1 </ b> H on the outer peripheral edge. Each is formed.

  Referring to FIGS. 1 and 4, the inner ring 2 is a cylindrical shaft-like member, and outer teeth 21 (the number of teeth is 17) whose tooth shape is an involute are formed over the entire outer periphery thereof. ing. That is, the inner ring 2 is an external gear that is long in the axial direction, and a part of the inner ring 2 forms the external tooth side of the involute spline.

  Referring to FIGS. 1 and 5, the outer ring 3 has a hole through which the inner ring 2 passes, and outer teeth 31 are provided on the outer periphery. The external teeth 31 have an involute tooth profile. The external teeth 31 are 24 in number so that the external teeth 31 are fitted with the internal teeth 1H6 of the housing 1 to form an involute spline. Not provided. A conical surface 32 that faces inward in the radial direction and a cylindrical surface 33 that extends in the axial direction from the reduced diameter end of the conical surface 32 are formed on the inner periphery of the outer ring 3. The conical surface 32 is preferably inclined by 10 ° to 40 ° with respect to the cylindrical surface 33 (axial direction), and is inclined by 30 ° in the illustrated embodiment.

  Referring to FIGS. 1 and 6, the inner ring 4 has a hole through which the inner ring 2 passes, and an inner tooth 41 is provided on the inner periphery. The tooth profile of the inner teeth 41 is also involute and has 17 teeth. The inner teeth 41 mesh with the outer teeth 21 of the inner ring 2 to form an involute spline. On the outer periphery of the inner ring 4, there are formed a conical surface 42 facing outward in the radial direction and a cylindrical surface 43 extending in the axial direction from the enlarged end of the conical surface 42. The opposed conical surface 42 is preferably inclined by 10 ° to 40 ° with respect to the cylindrical surface 43 (axial direction), and is inclined 30 ° in the illustrated embodiment.

The description will be continued mainly with reference to FIG. 1. The inner ring 2, the outer ring 3, and the inner ring 4 are mounted in the housing 1 as follows.
First, the outer teeth 21 of the inner ring 2 forming the involute spline and the inner teeth 41 of the inner ring 4 are fitted together, and the inner ring 4 is positioned in the housing space 1H3 of the housing 1. At this time, the axial end surface of the inner ring 4 and the axial end surface of the inner ring 2 (both right sides in FIG. 1) are brought into contact with the end plate 1H1. Next, the outer ring 3 is inserted into the inner ring 2 so that the conical surface 32 comes into contact with the opposing conical surface 42 of the inner ring 4, and the outer teeth 31 forming the involute spline and the inner teeth 1H7 of the housing 1 are fitted together. It is located in the housing section 1H3 of the housing 1. Then, the lid member 1 </ b> S is fixed to the main body 1 </ b> H of the housing 1 using the bolt 5. When the lid member 1S is fixed to the main body 1H of the housing 1, the axial end surface of the outer ring 3 is pressed by the lid member 1S, and the conical surface 32 of the outer ring 3 and the opposing conical surface 42 of the inner ring 4 come into contact with each other. Press in the axial direction.

  In the torque limiter of the present invention, the outer ring 3 and the inner ring 4 are in contact with each other at conical surfaces and have a structure similar to a spring device known as a so-called “ring spring”. Both rings are elastically deformed by the axial load applied by the lid member 1S, and the inner ring 3 is reduced in diameter, while the outer ring 4 is increased in diameter. Along with this elastic deformation, a frictional force acts between the conical surfaces of both rings, and the frictional force is very small even if the relative displacement in the axial direction of the outer ring 3 and the inner ring 4 is very small. Large value. Therefore, even if the torque limiter of the present invention is small, a large rotational torque can be transmitted between the inner ring 2 and the housing 1. Specifically, this rotational torque is transmitted from the inner ring 2 to the inner ring 3, and is transmitted from the inner ring 4 to the outer ring 3 and further from the outer ring 3 to the housing 1 by the frictional force between the conical surfaces.

Here, in the torque limiter of the present invention, the inner ring 4 and the outer ring 3 are respectively engaged with the inner ring 2 and the housing 1 which are counterparts by involute splines. That is, the inner ring 2 and the inner ring 4 are engaged with each other so as not to rotate relative to each other by fitting the outer teeth 21 of the involute tooth shape and the inner teeth 41 of the inner ring 4, and similarly, the outer ring 3 and the housing 1. Also, the involute tooth-shaped outer teeth 31 and the inner teeth 1H7 are fitted and engaged.
As described above, in the torque limiter of the present invention, since the rotational torque is transmitted to the inner ring 2 and the housing 1 by the contact of the involute tooth shapes having a large number of teeth, a large rotational torque is generated between the inner ring 2 and the housing 1. , The rotational torque is distributed to many teeth of the involute spline, and the force acting on each tooth becomes small. Further, the contact portion between the involute tooth shapes which are curved surfaces does not have a portion causing a sudden cross-sectional change such as a corner portion, and stress concentration can be avoided to prevent generation of cracks.

  Further, the external teeth and the internal teeth constituting the involute spline are the tooth profile of the involute gear itself (for example, the inner ring 2 is in the form of a hollow gear). An involute gear is a gear that is very commonly used as a rotation transmission component, and a processing machine that processes such a gear with high accuracy is always provided in a factory as a general-purpose processing device. Involute spline portions such as the inner ring 4 and the outer ring 3 of the present invention can be easily formed with high accuracy using such a processing machine. Therefore, when comparing the engagement means that engages with the projection and the groove having a square cross section, the manufacturing cost is low, and the rotation play of the engagement portion can be eliminated, and the rotation transmission device is easy to use. It will be.

In the first embodiment of FIG. 1 and the like, the external teeth 31 of the outer ring 3 and the internal teeth 1H7 of the housing 1H constituting the involute spline are both modules: m = 1, but the external teeth 31 are While the dislocation coefficient = 0 is a standard tooth profile, the internal tooth 1H7 is a tooth profile having a normal dislocation amount with a dislocation coefficient = 0.2, and the dislocation amounts are set to be different from each other. There should be a slight clearance between the inner and outer teeth.
By setting the tooth shape in this way, in the torque limiter of the present invention, at the time of assembly, first, the operation of inserting the outer ring 3 into the housing 1H is facilitated. Then, when the lid member 1S presses the outer ring 3 in the axial direction and expands the diameter, the amount of dislocation existing between the external gear 31 of the outer ring 3 and the internal gear 1H7 of the housing 1 is obtained. Therefore, the rotation play between the outer ring 3 and the housing 1 is eliminated.
In the first embodiment, the tooth shapes of the inner teeth 41 of the inner ring 4 and the outer teeth 21 of the inner ring 2 constituting the other involute spline are both standard tooth shapes with a module: m = 1 and a dislocation coefficient = 0. It is. However, if desired, the dislocation amounts of the inner teeth 41 and the outer teeth 21 can be made different.

Next, the operation of the torque limiter of the first embodiment will be described mainly with reference to FIG. This torque limiter is, for example, a rotation that is interposed to protect the motor of the drive source from overload in a rotation transmission system that automatically opens and closes the lid of the personal computer, the toilet seat, etc., as a driven member by the motor as the drive source. It is a transmission device, and an inner ring 2 is connected to a motor as an input member, and a housing 1 is connected to a lid of a personal computer as an output member.
If the torque for rotating the inner ring 2 and the housing 1 relative to each other is not more than a predetermined value, that is, the driven member is in a normal state, the opposing conical surface 42 of the inner ring 4 engaged with the inner ring 2 and the housing 1 Due to the frictional force between the engaged outer ring 3 and the conical surface 32, the inner ring 2 and the housing 1 rotate integrally, and the driven member can be driven by the rotational drive from the motor. In the torque limiter of the present invention, the outer ring 3 and the inner ring 4 form a spring device known as a so-called “ring spring”, which is elastically deformed by an axial load and has a very large frictional force therebetween. Is generated. Therefore, even if the torque limiter of the present invention is small, a large torque can be transmitted between the inner ring 2 and the housing 1.
Furthermore, in the torque limiter according to the present invention, the outer ring 3 and the inner ring 4 are engaged with each other by the involute spline so that they cannot rotate relative to each other, so that rotation backlash between the input member and the output member is avoided, Generation of cracks in the engaging portion is also avoided.

  On the other hand, when a rotational torque larger than a predetermined value is applied between the inner ring 2 and the housing 1, such as when the lid of a personal computer that is a driven member is pressed by hand, the conical surface 32 and the inner ring 4 of the outer ring 3. The outer ring 3 and the inner ring 4 rotate relative to each other by overcoming the frictional force between the opposing conical surfaces 42 of the outer ring 3 and the outer ring 3. That is, a slip occurs between the inner ring 2 and the housing 1, the motor and the driven member are shut off, and the motor is protected from overload.

  Next, a second embodiment of the torque limiter according to the present invention will be described with reference to FIGS. FIG. 7 is a diagram showing the overall structure of a second embodiment of the torque limiter according to the present invention, and FIGS. In the following description, the same components as those in the first embodiment are not described and only “′” is indicated by the same reference numerals as those in the first embodiment.

Referring to FIG. 8 together with FIG. 7, the outer periphery of the housing space 1H3 ′ in the housing 1 ′ (that is, the inner periphery of the main body portion 1H ′) is a small protrusion having an arcuate cross section that protrudes relatively small radially inward. A portion 1H8 ′ and a large protruding portion 1H9 ′ having a semicircular cross section that protrudes relatively large are formed. A plurality of small protrusions 1H8 'and a large protrusion 1H9' are provided at equal angular intervals in the circumferential direction (three in the illustrated embodiment). Are alternately arranged at equal angular intervals in the circumferential direction. Each large protrusion 1H9 'is formed with a screw hole 1H5' that faces the opening 1H2 'and extends in the axial direction.
Further, with reference to FIG. 9, the outer peripheral edge of the lid member 1S ′ has three small holes 1S1 ′ corresponding to the screw holes 1H5 ′ and three notches that mesh with the small protrusions 1H8 ′. A notch 1S3 'is formed. Then, three arc-shaped projecting portions 1S4 'projecting to the other side in the axial direction are formed in the substantially intermediate portion in the radial direction of the lid member 1S' and aligned with the respective notches 1S3 'in the circumferential direction.

  Referring to FIG. 10 together with FIG. 7, the inner ring 2 ′ is a cylindrical shaft-like member, and outer teeth 21 (the number of teeth is 26) having an involute tooth shape are formed on the outer periphery thereof over the entire length. ing. That is, the inner ring 2 is an external gear that is long in the axial direction, and a part of the inner ring 2 forms the external tooth side of the involute spline. Such an inner ring 2 ′ is provided with appropriate positioning means used when the inner ring 2 ′ is disposed in the housing 1 ′. In the illustrated embodiment, the positioning means is a ring-shaped collar 26 ', which is press-fitted into the inner ring 2' and substantially axially intermediate, as will be clearly understood by referring to FIG. Located in position. The positioning means is not limited to a collar, and may be a pin, an E-ring, or the like. Further, in the case where positioning is not required when the inner ring 2 ′ is disposed in the housing 1 ′, positioning means need not be provided on the inner ring 2 ′.

  Referring to FIG. 11 together with FIG. 7, the outer ring 3 ′ includes an outer flat part 34 ′ in which a hole penetrating the inner ring 2 ′ is formed, and a conical part connected to the outer periphery of the outer flat part 34 ′. It consists of plate-shaped metal which has 35 '. Inner teeth 31 ′ are provided on the inner periphery of the outer plane portion 34 ′. The tooth shape of the inner teeth 31 ′ is involute, and the number of teeth is 26. The conical portion 35 'is preferably inclined by 10 to 40 ° with respect to the axial direction, and is inclined 20 ° in the illustrated embodiment. A conical surface 32 ′ is provided on the inner periphery of the conical portion 35 ′.

  Referring to FIG. 12 together with FIG. 7, the inner ring 4 ′ includes an inner flat surface portion 44 ′ in which a hole penetrating the inner ring 2 ′ is formed, and an opposing surface connected to the inner periphery of the inner flat surface portion 44 ′. It consists of plate-shaped metal which has a cone part 45 '. In the outer peripheral edge portion of the inner plane portion 44 ′, three small holes 46 ′ corresponding to the screw holes 1 H 5 ′ and three notches 47 ′ engaged with the small protruding portions 1 H 8 ′ are formed. . The opposing conical portion 45 'is preferably inclined by 10 to 40 ° with respect to the axial direction, and in the illustrated embodiment, it is inclined by 20 °. An opposing conical surface 42 ′ is provided on the outer periphery of the opposing conical portion 45 ′.

  In the torque limiter of the present embodiment, both the outer ring 3 ′ and the inner ring 4 ′ are manufactured from a plate-like metal by press molding. As in this embodiment, the outer ring 3 'and the inner ring 4' are both made of a plate-like metal, and have a flat surface portion (34 'and 43') and a contiguous portion (35 ') connected to it (opposite). And 44 ′), the outer ring 3 ′ and the inner ring 4 ′ can be formed from an appropriate metal plate by an easy-pressing process, so that the production efficiency of the torque limiter can be improved. It can be raised and the manufacturing cost can be reduced, which is convenient for mass production.

  Mainly with reference to FIG. 7, in the present embodiment, the outer ring 3 'is engaged with the inner ring 2' by the involute spline so as not to be relatively rotatable. On the other hand, the inner ring 4 ′ is engaged with the housing 1 ′ in a relatively non-rotatable manner by the cooperation of the notch 47 ′ and the small protrusion 1 </ b> H <b> 8 ′. When the inner ring 4 ′ and the housing 1 ′ are engaged so as not to rotate relative to each other, the small hole 46 ′ of the inner ring 4 ′ is aligned with the screw hole 1 H 5 ′ of the housing 1 ′. And inner ring 4 'is fixed to main body 1H' with cover member 1S 'with screw 5'. If desired, also in the present embodiment, the tooth shapes of the external teeth and the internal teeth constituting the involute spline may be set to have different dislocation amounts. Further, the inner ring 4 ′ may be coupled to the housing 1 ′ by an involute spline so as not to be relatively rotatable.

  Also in the torque limiter of the present embodiment, when the components are combined as required, the outer ring 3 'and the inner ring 4' form a spring device known as a "ring spring". One of a driving member such as a motor and a driven member such as a machine part is connected to the inner ring 2 ′, and the other is connected to the housing 1 ′, which is the same as the torque limiter of the first embodiment described above. It is possible to achieve the operational effects.

  In the torque limiter of the present embodiment, the conical surface 32 ′ of the outer ring 3 ′ and the conical surface 42 of the inner ring 4 ′ are further adjusted by adjusting the tightening allowance of the screw 5 to advance and retract the lid member 1 S ′ in the axial direction. The frictional force between the first and second torques is adjusted, so that the predetermined value of the rotational torque can be appropriately adjusted. At this time, since the arc-shaped protrusion 1S4 ′ is provided on the lid member 1S ′, the lid member 1S ′ can press the inner ring 4 ′ satisfactorily.

  On the other hand, in the torque limiter of the present embodiment, the inner ring 4 ′ is fixed to the main body 1H ′ of the housing 1 ′ by the screw 5 ′ together with the lid member 1S ′ (in other words, the inner ring 4 ′ is fixed to the lid member 1S ′. Therefore, the lid member 1S ′ can be omitted if desired. When the lid member 1S ′ is omitted, the frictional force between the conical surface 32 ′ of the outer ring 3 ′ and the opposing conical surface 42 ′ of the inner ring 4 ′ cannot be adjusted, but the number of parts is reduced. It can contribute to reduction of manufacturing cost and weight reduction.

  The preferred embodiment of the torque limiter of the present invention has been described in detail above. In the above embodiment, one pair of the outer ring and the inner ring is provided. However, the present invention is not limited to this, and a plurality of pairs of the outer ring and the inner ring may be provided depending on the intended use. By increasing the number of outer rings and inner rings, the frictional force between the conical surface and the opposing conical surface increases, and the slip torque can be set to a larger value. Even when a plurality of pairs of the outer ring and the inner ring are arranged, at least one of the outer ring and the inner ring needs to be engaged with the other party so as not to be relatively rotatable by the involute spline. In the above embodiment, at least one of the outer ring and the inner ring is coupled to the other side so as not to be relatively rotatable by an involute spline in which the cross-sectional shape of the inner teeth and outer teeth approximates a trapezoidal shape. Then, the cross-sectional shape may be coupled to the other party so as not to rotate relative to each other by involute serration having a triangular shape.

1: Housing 2: Inner ring 3: Outer ring 32: Conical surface 4: Inner ring 42: Opposing conical surface 5: Screw

Claims (5)

A torque limiter comprising a shaft-shaped inner ring and a housing, and when a rotational torque of a predetermined value or more is applied between the inner ring and the housing, the two rotate relatively;
An outer ring and an inner ring disposed adjacent to each other surrounding the inner ring are installed in the housing to have a common central axis;
A conical surface is formed on the inner periphery of the outer ring, and an opposing conical surface that is in contact with the conical surface and presses in the axial direction is formed on the outer periphery of the inner ring. One of the rings is engaged with the inner ring and the other is engaged with the housing in a relatively non-rotatable manner,
When a rotational torque of a predetermined value or more is applied between the inner ring and the housing, the inner ring and the inner ring against the frictional force between the conical surface of the outer ring and the opposing conical surface of the inner ring. The housing is configured to rotate relative to the housing; and
A torque limiter, wherein at least one of the outer ring and the inner ring is engaged with an opposite side by an involute spline so as not to be relatively rotatable.   The torque limiter according to claim 1, wherein tooth shapes of external teeth and internal teeth constituting the involute spline are set to have different dislocation amounts.   The housing is provided with the outer ring and the inner ring, and has a receiving space in which an opening is provided at an end portion in the axial direction, and the opening has a conical shape of the outer ring while shielding the opening. The torque limiter according to claim 1 or 2, further comprising a lid member that axially presses the surface and the opposing conical surface of the inner ring in the axial direction.   The torque limiter according to any one of claims 1 to 3, wherein outer teeth are formed on the outer circumference of the inner ring and the housing over the entire length in the axial direction.   The torque limiter according to any one of claims 1 to 3, wherein both the outer ring and the inner ring are formed of a plate-shaped metal including a flat portion and a conical portion connected thereto.