JP2005188559A - Electromagnetic clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic clutch in which the axial dimension of an electromagnetic clutch section is reduced as compared with a clutch of the magnet coil type (in which the clutch is engaged by supplying the electricity to the magnet coil) and shapes of a rotor and a magnet having good assembling facility (productivity) are adopted, as an electromagnetic clutch of the type (the de-energization operation type) such that a permanent magnet is used, which clutch is utilized as a rotation transmission device in a power transmission path or the like. <P>SOLUTION: The electromagnetic clutch includes the rotor 4 secured to a rotary shaft 1, an armature 5 provided so as to be elastically separated from the rotor by means of a disk spring 7 of elastic material, the armature 5 being attracted toward the rotor 4 by the magnetic force of the permanent magnet 8 fitted in a slit of the rotor 4, and the electromagnetic coil 6 installed in a recess portion of the rotor 4. An inner ring 4b and an outer ring 4a of the rotor 4 are connected to each other through connecting columns 9. The number of the connecting columns is set to a minimum, i.e, three, so that the axial dimension of the clutch section A is minimized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic clutch in which power transmission and interruption switching in a power transmission path or the like can be controlled using electromagnetic force.

  The clutch, which is a means for transmitting and interrupting the power between the two rotating shafts, is required to promptly switch the transmission of power during traveling when applied to various applied devices such as vehicles. It is desirable to be able to quickly control transmission and interruption of power by a control signal from the control unit. As a clutch that satisfies this requirement, an electromagnetic clutch or an electromagnetic clutch that controls engagement and disconnection of the clutch is integrated into a two-way clutch that transmits power in two directions of forward and reverse rotation by engagement and disconnection of the clutch. There is an electromagnetic two-way clutch.

  As for the above-mentioned electromagnetic clutch, the electromagnetic clutch has an electromagnetic coil that is engaged when the current is not energized and engages the electromagnetic clutch to transmit power, and the electromagnetic clutch is engaged when a current is passed through the electromagnetic coil. There is an electromagnetic coil type to be combined. The non-excitation operation type electromagnetic clutch is used when there is a problem in safety if power is not transmitted when the electromagnetic coil is disconnected or the power source is unusable. Generally, the clutch is engaged by a permanent magnet.

  As an example of the non-excitation operation type electromagnetic clutch, “Magnetic Clutch with stationary winding” is disclosed in Patent Document 1. The electromagnetic clutch according to this publication is provided with a hollow shaft on the outer side of the middle shaft and an armature provided on the middle shaft so as to be opposed to and contact with a rotor provided on the hollow shaft through a friction-resistant material. The spring between the armature and the armature urges the armature away from the rotor, and the rotor is provided with a strong permanent magnet, and the magnetic force normally attracts the armature to the rotor with a suction force that is greater than the spring force to make frictional contact. The power is transmitted from the middle shaft to the hollow shaft.

  The rotor is provided with an electromagnet fixed to the fixed portion as appropriate, and when the clutch is to be disconnected, the magnetic flux is generated in the electromagnet in the direction opposite to the direction of the magnetic flux of the permanent magnet. And the armature is pulled away from the rotor by a spring force to interrupt transmission of rotation to the rotor.

  On the other hand, as an example of an electromagnetic two-way clutch, Patent Document 2 discloses a “rotation transmission device” in which an electromagnet unit is combined adjacent to a clutch member that transmits power by engaging a roller. In the electromagnetic two-way clutch according to this publication, a roller as an engaging member is placed in a pocket between an inner member connected to one shaft and an outer ring connected to the other shaft and disposed outside the inner member. A cage surface is formed between the opposing surfaces of the inner member and the outer ring, and a cam surface is formed between the opposing surfaces of the inner member and the outer ring, so that the roller is not engaged between the cage and the outer ring or the inner member. An elastic member for holding is incorporated, an armature is attached to the end of the cage so as to be movable in the axial direction, and an electromagnet for adsorbing the armature is incorporated.

  The above-described non-excitation operation type electromagnetic clutch is attracted by the attraction force of the permanent magnet more than trying to separate the engagement between the armature and the rotor by the force of the elastic member. The electromagnetic two-way clutch may be a non-excited operation type electromagnetic clutch. In this case, the attractive force between the armature and the rotor needs to be stronger than that of the elastic member. For this reason, a strong magnet is used as the permanent magnet, and the mutual structure and shape are determined so that the magnetic flux to the armature does not decrease. However, in any of the conventional types of electromagnetic clutches described above, the configuration of the clutch portion including the armature, the rotor, and the permanent magnet has a large axial dimension and the productivity is insufficient unless the dimensional accuracy of each member is ensured. As a result, there is a problem that the size of the electromagnetic clutch portion is increased.

  The above problem specifically includes two structural problems. First, the amount of magnetic flux is generally the product of the cross-sectional area of the member in the direction crossing the flow of magnetic flux and the average magnetic flux density of that part. But it is the same. The upper limit of the amount of magnetic flux is determined by the portion where the magnetic flux density is saturated. Therefore, when the size of the electromagnetic clutch portion is reduced in the electromagnetic coil type electromagnetic clutch, it is necessary that only a specific portion does not saturate the magnetic flux density. For this reason, when the magnetic characteristics of the materials of the rotor, armature, and field coil, which are magnetic circuit constituent members, are substantially the same, the dimension of the cross-sectional area in the direction across the flow of magnetic flux is determined so that the magnetic flux density of each part is uniform.

For example, in the magnetic circuit of the magnetic coil 6 including the rotor 4, the armature 5, the field coil 6a, and the yoke 6b shown in FIG. 13, the magnetic flux density in the portions indicated by arrows f ₁ and f ₂ is increased. The axial dimension of the slit portion of the rotor is determined by the portion. On the other hand, in the permanent magnet type electromagnetic clutch shown in FIG. 13B, since the magnetic flux of the permanent magnet 8 is radially oriented, the magnetic pole is directed from the outer diameter side to the inner diameter side, and the magnetic flux φ _{2 of the} permanent magnet is This is the product of the cross-sectional area of the magnetic pole of the permanent magnet and the surface average magnetic flux density Br ₂ of the permanent magnet.

Here, in contrast, it is assumed that a magnetic flux φ ₂ equal to the magnetic flux φ _{1 in} the electromagnetic coil type (without permanent magnet) clutch portion shown in FIG. However, as a permanent magnet that is actually used, the magnetic flux density Br ₂ of the rare earth sintered magnet is about 1 T even if the permeance coefficient is infinite, and about 0.6 T for the rare earth bonded magnet. Since the coefficient is about 1-2, the surface magnetic flux density is further reduced. When the permanent magnet is inserted into the slit, the saturation magnetic flux density Br ₁ of the rotor material is about 1.5 T. For example, when Br ₂ is 0.6 to ₁ T, the rotor is φ ₂ = φ _1. The cross-sectional area of the slit, which is the magnetic pole part, is 1.5 to 2.5 (1.5 ÷ 1 to 1.5 = 0.6) times or more as compared with the electromagnetic coil type.

Therefore, as a first problem, assuming that the radii of the respective parts are substantially equal, the cross-sectional area is proportional to the axial dimension. Therefore, the axial dimension L ₂ of the rotor of the permanent magnet clutch shown in FIG. becomes 1.5 to 2.5 times the dimension L _1, the overall axial length becomes longer. Further, since the permanent magnet is fixed with a gap from the contact surface of the armature and the rotor so as not to directly contact the armature, there is a problem that L ₂ is further increased by this gap.

Secondly, in the permanent magnet type, there is a problem that the gap between the rotor and the field coil (g _{1 in} FIG. 14A) cannot be approached, and the overall axial dimension is further increased. The reason is as follows. When there is a gap between the armature and the rotor, the magnetic flux generated from the magnet flows not only to the armature but also to the electromagnetic coil side. As shown in FIG. 14B, when the gap between the field coil and the rotor becomes small as g ₂ , the magnetic resistance between the rotor and the field coil decreases and the magnetic flux flowing toward the field coil increases (see FIG. 14). 14, the portion that changes from the dotted line in FIG. 14 (a) to the dotted line in FIG.

Accordingly, the attractive force between the armature and the rotor has characteristics as shown in FIG. 14C, and if the gap between the field coil and the rotor is made too small, the attractive force suddenly increases as the gap between the armature and the rotor increases. Decrease. Therefore, if the gap between the armature and the rotor and the elastic member are not managed accurately, the armature cannot be attracted by the attracting force of the permanent magnet when the energization of the electromagnetic coil is interrupted. The gap between the rotor and field coil could not be approached.
U.S. Pat. No. 3,055,470 JP 11-336799 A

  In the present invention, in consideration of the above-mentioned various problems, an electromagnetic clutch (non-excitation operation type) using a permanent magnet is used as an electromagnetic clutch that is used as a rotation transmission device in a power transmission path or the like. Rotation device of the electromagnetic clutch type that employs a rotor and magnet shape that has better assembly (productivity) and the axial dimension of the clutch part does not become larger than the type (the clutch is engaged by energizing the electromagnetic coil) It is an issue to provide.

  As a means for solving the above-described problems, the present invention provides a rotor for transmitting rotation between rotating shafts, an armature that frictionally engages with the rotor so as to move only in the axial direction and transmit the rotation, Inner and outer ring members each having a permanent magnet provided on the rotor for engaging the armature with the rotor and an electromagnet for engaging and blocking the armature and separated by a slit provided on the rotor for inserting the permanent magnet An electromagnetic clutch having a minimum number of connecting pillars for connecting them to each other, which is necessary in terms of magnetic flux density and member strength, and which minimizes the total gap amount required for assembling, is employed.

  The electromagnetic clutch of the present invention configured as described above is a rational and compact structure having the shortest electromagnetic clutch length in the axial direction as the structure of the main part of the electromagnetic clutch that transmits and blocks power between the rotating shaft and the rotating shaft. In addition, a structure having the best assembly (productivity) can be obtained. In this case, the most characteristic configuration is that the rotor is divided into inner and outer rings for attaching permanent magnets to the rotor, and the number of connecting columns connecting both rings is minimized. As conditions for adopting this minimum number, it is necessary that the magnetic flux density flowing from the rotor to the armature and the strength for connecting both rings are sufficient, and that the total gap amount necessary for assembling is minimized.

  The actual number of connecting pillars satisfying such a condition is three when other various conditions are set in total, and this is the most reasonable number. Other conditions are conditions in which the mutual axis of the outer ring, the degree of restraint around the axis, and the longitudinal cross-sectional area of the connecting column in the axial direction are minimized, among other factors determined by the number. By setting the axial dimension of the clutch portion so as to satisfy such conditions, the clutch portion has a minimum axial length, and a rational and powerful clutch action can be obtained.

  On the other hand, as another means for solving the above problems, a rotor for transmitting rotation between the rotating shafts, an armature that frictionally engages with the rotor so as to move only in the axial direction and transmit the rotation, An electromagnetic clutch comprising a permanent magnet provided on the rotor for engaging the armature with the rotor, and an electromagnet for engaging and shutting off the armature, and a recess provided on the surface of the rotor facing the yoke of the electromagnetic coil It can also be.

  By adopting an electromagnetic clutch having such a configuration, as in the first aspect of the invention, the structure of the main part of the electromagnetic clutch that transmits and blocks power between the rotating shaft and the rotating shaft is Therefore, it is possible to obtain a rational, compact and good magnetic flux configuration. In this case, the most characteristic configuration is that a recess is provided on the opposing surface of the rotor that faces the yoke of the electromagnetic coil, and the gap between the end of the field coil and the rotor inner surface is reduced, but the distance between the yoke and the rotor inner surface is the recess. This increases the magnetic resistance between the yoke and the rotor, and even when there is a gap between the armature and the rotor, the magnetic flux of the permanent magnet hardly flows to the field coil side, and the magnetic flux to the armature side does not decrease. . Further, since the concave portion is provided in the rotor, the weight is reduced.

  In addition, a roller clutch having a roller as an engagement element is provided in the electromagnetic clutch according to any of the first and second aspects of the invention, and the transmission and disconnection of power between the inner member and the outer member of the roller clutch are performed by the electromagnetic clutch. An electromagnetic two-way clutch that is configured to perform transmission and disconnection between the rotor and the armature can also be used.

  In such an electromagnetic two-way clutch, the axial dimension of the electromagnetic clutch portion can be designed to the minimum, and therefore rational arrangement and configuration are possible, and the two-way clutch has the characteristics of the electromagnetic clutch. Functionality is further improved.

  In both of the electromagnetic clutches of the first and second inventions, in the structure of the clutch portion, the axial dimension is minimized, a reasonable and sufficient magnetic flux density is exerted on the armature, and a compact and economical electromagnetic clutch can be obtained. There are advantages.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a main longitudinal sectional view of an electromagnetic clutch as a rotation transmission device of the first embodiment. The electromagnetic clutch of this embodiment is a kind of non-excited operation type electromagnetic clutch, and its basic principle configuration is the same as that shown in Patent Document 1, but the detailed configuration is slightly different in the illustrated example. . Reference numeral 1 denotes a rotating shaft (input shaft) for transmitting rotational power, and reference numeral 2 denotes a rotating shaft for transmitting power as an output shaft formed in a rotating disk shape. An electromagnetic clutch A is provided between the rotating shafts 1 and 2 for transmitting and interrupting power. The electromagnetic clutch A includes a rotor 4, an armature 5, and an electromagnetic coil 6.

  The rotor 4 is integrally fixed to the rotating shaft 1 and has a U-shaped cross section as shown in the figure. The electromagnetic coil 6 is formed against the recess 4i between the outermost flange portion outside the boss portion. Is inserted with a predetermined gap from the inner surface of the rotor, and the armature 5 is frictionally engaged with the outer surface of the rotor 4 on the opposite side surface of the rotor 4, so that the armature 5 and the electromagnetic coil 6 sandwich the rotor 4 therebetween. They are installed facing each other. As will be described later, in the rotor 4, an outer ring 4a and an inner ring 4b are integrally connected by a connecting column 9, and a permanent magnet 8 is inserted into a groove (slit) between both rings.

  The armature 5 is formed in a disk shape with a magnetic material, and an inner hole is inserted into a boss portion of the rotary shaft 2 that is an output shaft, and is fitted into a spline or a protruding piece 2 a provided in the boss portion. Although it is movable in the axial direction, it is provided so as to rotate integrally with the rotating shaft 2. Also, the armature 5 is usually pressed by an elastic member such as a disc spring 7 provided at the base of the boss so as not to frictionally engage the outer surface of the rotor 4. As shown in FIG. 1B, the outer surface of the permanent magnet 8 is formed with a slight gap t from the outer surface of the rotor 4 so that the opposed surface of the armature 5 and the outer surface of the permanent magnet 8 do not directly contact each other. In addition, the position of the permanent magnet 8 is set.

  The electromagnetic coil 6 surrounds the field coil 6a with the yoke 6b and applies magnetic flux generated when the field coil is energized to the rotor and the armature via the end surface or outer peripheral surface of the yoke 6b to generate electromagnetic force. In this example, the electromagnetic coil 6 is stationary and fixed by a fixing means (not shown) as appropriate to a support member 3 that rotatably supports the rotary shaft 1. The support member 3 may have any structure and shape other than the illustrated example. Although not shown, the electromagnetic coil 6 is connected to a power supply line from the outside, and energization / non-energization is controlled by a command from the control circuit.

  As shown in FIGS. 2 to 5, in the rotor 4, the outer ring 4 a and the inner ring 4 b are integrally connected by a connecting column 9 at a plurality of locations (three locations in the illustrated example). The connecting pillar 9 is made of the same magnetic material as that of the outer ring 4a and the inner ring 4b, and is manufactured as an integral body. The connecting column 9 is provided to attach the permanent magnet 8 to a groove (slit) between the rings so that the outer ring, the outer ring-shaped outer ring, and the inner rings 4a and 4b are not separated from each other. However, for example, both the conventional general (a) electromagnetic coil type and (b) permanent magnet type shown in FIG. 7 are formed of the same material as the ring member.

  FIG. 7 shows the flow of magnetic flux in each case. (A) shows magnetic fluxes fa, fb, fb 'by the electromagnetic coil 6, and (b) shows magnetic fluxes fa, fb, fb' by the permanent magnet 8. The gaps on the inner diameter side and outer diameter side of the electromagnetic coil 6 inserted between the outer flange portion of the rotor 4 and the projecting boss portion at the center are set to a small enough dimension that the magnetic flux fb can easily flow.

  In addition, since the rotor 4 has a recess 4i formed on one side thereof, a portion other than the outer and inner rings 4a and 4b connected by the connecting pillar 9 is a groove 4r, and both the rings 4a and 4b are Are separated from each other. The permanent magnet 8 fitted in the groove 4r is formed as a flat donut-shaped circular ring, and a shallow recess 8s is partially formed on one side only at a position corresponding to the connecting column 9. The rotating shaft 1 is integrally fixed to the center hole 1r of the rotor 4 using a spline or a key.

  2 to 5, the total number of gaps 9a and 9a provided on both sides of the connecting column 9 is the smallest, and the axial dimension of the permanent magnet 8 is the smallest. The book is illustrated as being most space efficient. The reason will be described below. That is, as described above, since the connecting pillar 9 is made of the same magnetic material as the outer and inner rings 4a and 4b, the magnetic flux of the permanent magnet flows to the armature 5 through both the rings 4a and 4b of the rotor. However, at the same time, the magnetic flux flows through the connecting column 9 and the magnetic flux flowing through the armature 5 decreases accordingly. Therefore, it is better that the total cross-sectional area of the connecting columns is as small as possible.

  The cross-sectional area of the connecting column 9 in the axial direction needs to be a cross-sectional area that is more than the minimum necessary for maintaining the strength to hold the outer and inner rings 4a and 4b together. The strength of the connecting columns is sufficient if the cross-sectional area of each connecting column x the number of columns is equal to or greater than the required strength, and how many columns are selected regardless of how many columns the total cross-sectional area is divided into. The influence of is relatively small, and generally four that are easy to manage dimensions are often selected. For example, Japanese Patent Application No. 2002-356888, which is a prior application of the present applicant, shows an example in which four connecting pillars are provided.

  The above is the influence on the magnetic flux and strength of the connecting column, but the following conditions must also be considered. When inserting the permanent magnet 8 into the groove (slit) 4r, considering the assemblability of the permanent magnet 8 with respect to the groove 4r, i.e., productivity, in general, in order to avoid interference between the connecting column 9 and the permanent magnet 8 with respect to the groove 4r. It is necessary to provide a certain gap 9a (= d). Accordingly, if such a gap 9a is provided, the total gap amount = number of columns × d × 2 increases in proportion to the number of connecting columns, and therefore the total magnetic pole cross-sectional area of the permanent magnet increases to the number of connecting columns. If all of them are equal even if they are divided, when the number of connecting columns is three, the size of the magnet in the direction of the rotation axis is also minimized. The reason is as follows.

  First, let us consider a constraint state of the mutual degrees of freedom of the outer and inner rings 4a and 4b with respect to an increase or decrease in the number of connecting columns. FIG. 8 shows a schematic diagram of the rotor 4 when the number of the connecting pillars 9 is changed to 1 to 4, and the corresponding change in the number of degrees of freedom is shown in Table 1 below.

  In the above table, the number of degrees of freedom of the inner ring 4b relative to the outer ring 4a of the rotor 4 divided by the connecting column 9 and the groove (slit) 4r when the connecting column is regarded as a fulcrum is tabulated. is there. For example, when the connecting column 9 is set to 1 in FIG. 8A, if the connecting column is handled as a fulcrum, the inner ring 4b is centered on the fulcrum, and either the X-axis or the Z-axis with respect to the outer ring 4a. It is also movable in the direction of, and is not constrained, and can also rotate around the Y axis around the fulcrum. If the connecting column 9 is 2, it can rotate only around the Y axis around the fulcrum of the upper and lower connecting columns. If the number is 3 or more, all the axes are restricted. Therefore, the number of constraints is as shown in Table 1.

  Next, when the connecting columns are divided into 1 to 4 as the minimum necessary area to maintain the strength of supporting the outer and inner rings of the rotor with respect to each other, the total axial cross-sectional area of all the connecting columns is Comparing the total axial cross-sectional areas in this case, when the number of connecting columns is 3 or more, all the degrees of freedom are constrained, so the sum of the axial cross-sectional areas of all the connecting columns becomes substantially equal. Therefore, even if it is divided into three or more, the strength does not change much. On the other hand, if the number is 1 or 2 of 3 or less, there is a degree of freedom that is not constrained in this case. Therefore, if the cross-sectional area of the column is widened for reasons of strength, it tries to constrain to a free point that is not constrained.

  For this reason, the total cross-sectional area of the connecting column in the axial direction is larger than when the number is three. Therefore, when the number is three or more, the total cross-sectional area of the connecting column is the smallest, and among them, the smallest three gaps allow the most efficient use of the magnet space into which the permanent magnet is inserted. This is because the width dimension of the magnet is minimized. If the above various conditions are judged comprehensively, it is understood that it is optimal to set the number of connecting columns to three. However, what is important in determining the optimum number 3 among the various conditions is the strength of the connecting columns, the influence on the magnetic flux, and the conditions for setting the gap.

  The electromagnetic clutch as the rotation transmission device of this embodiment configured as described above operates as a non-excitation electromagnetic clutch. In a state in which the energization to the electromagnetic coil 6 is interrupted, the magnetic flux of the permanent magnet 8 exits from one end and flows as a magnetic flux fa to the armature 5 as shown in FIG. 1B, and the yoke 6b of the electromagnetic coil 6 Also flows as magnetic flux fb. At this time, the attracting force of the armature 5 to the rotor 4 by the magnetic flux fa is set to be larger than the elastic force (separation force) for pulling the armature 5 away from the rotor 4 by the spring force of the disc spring 7 of the elastic member. Accordingly, the armature 5 frictionally engages with the outer surface of the rotor 4 and rotates together with the rotor 4, and rotational power is transmitted between the rotary shafts 1 and 2.

  When a current is passed through the electromagnetic coil 6, as shown in FIG. 6A, a magnetic flux fc opposite to the magnetic flux fb generated by the permanent magnet is generated in the yoke 6b (the field coil 6a is passed in the opposite direction). ), The magnetic flux fa generated by the permanent magnet 8 is also canceled by the magnetic flux fc to become a reduced magnetic flux fa ′, and the attractive force of the armature 5 is reduced. Since the armature 5 is movable in the axial direction and the disc spring 7 of the elastic member acts so as to pull the armature 5 away from the rotor 4, if the adsorption force acting on the armature becomes smaller than the spring force of the elastic member, the armature 5 moves axially away from the rotor 4 and the engagement of the electromagnetic clutch is released. When the energization of the electromagnetic coil 6 is interrupted, the initial state is restored, and torque can be transmitted between the armature 5 and the rotor 4 by the magnetic force of the permanent magnet.

  As the permanent magnet shown in FIGS. 1 to 5, a ring magnet provided with a groove in a part thereof was used. As the permanent magnet, a rare earth sintered magnet, a bonded magnet, or the like is used. Since the bonded magnet can have a flexible shape to some extent, it is used for the ring magnet. Since a sintered magnet cannot have a complicated shape, it is generally divided (8 ') in accordance with a groove as shown in FIG. 6 (b). In addition, when the shape of the magnet becomes large, there are cases where each of the three divided like the permanent magnet 8 "is further subdivided.

  FIG. 9 is a partial sectional view of a partial modification A ′ of the clutch portion A of the electromagnetic clutch as the rotation transmission device of the first embodiment. This modification A ′ is an example in which a recess 4 </ b> T is formed in a portion of the rotor 4 that faces the end surface of the yoke 6 b of the electromagnetic coil 6. This modification A ′ eliminates the inconvenience that the gap between the opposed surfaces of the rotor 4 and the electromagnetic coil 6 cannot be approached below a predetermined distance in the first embodiment, and reduces the axial dimension of the clutch portion A ′. The aim is to do. As shown in the drawing, the axial thickness of the rotor 4 is projected so that the inner peripheral edge 4PR of the outer ring 4a and the outer peripheral edge 4PR of the inner ring 4b are very close to the field coil 6a. Of these, the outer peripheral edge 4PR is formed integrally in a vertically continuous manner.

Therefore, the inner surface of the rotor 4 is not thickened at a position facing the end surface of the yoke 6b of the electromagnetic coil 6, thereby forming the ring-shaped surfaces of the recesses 4T and 4T on the inner surface of the rotor 4. About another structure, it is the same as 1st Embodiment, and the structure of 1st Embodiment is applied as it is. The reason for this configuration is as follows. That is, as shown in (a) of FIG. 10, reducing the gap between the opposing surfaces of the electromagnetic coil 6 g ₂ by thickening the overall thickness between the inner surface and the outer surface of the rotor 4, by the permanent magnet 8 A magnetic flux fb ′ is generated in addition to the magnetic flux fb as a flow passing through the end face of the yoke 6 b of the electromagnetic coil 6, and the magnetic flux fa to the armature 5 decreases accordingly.

In order to increase the magnetic flux by increasing the size of the permanent magnet 8, in order to keep the gap between the electromagnetic coil 6 and g ₂ small without increasing the thickness of the rotor 4 in parallel, the rotor If the inner surface of 4 is formed as the recesses 4T, 4T at positions facing the end surface of the yoke 6b, the amount of gap between the end surface of the yoke 6b and the inner surface recess 4T of the rotor 4 increases, so that the magnetic resistance increases. The magnetic flux fb ′ in FIG. As a result, the weight of the rotor can be reduced and the axial dimension of the clutch portion A ′ can be reduced. In addition, although the structure which provides a recessed part in the inner surface of the rotor 4 by this modification was demonstrated on the assumption that it provided in 1st Embodiment, you may employ | adopt independently with respect to the various electromagnetic clutch different from 1st Embodiment. .

  11 and 12 show the configuration of an electromagnetic clutch as a rotation transmission device of the second embodiment. This electromagnetic clutch is an electromagnetic two-way clutch in which an electromagnetic clutch unit C is incorporated in a roller clutch B having a roller as an engagement element. In the electromagnetic clutch unit C, components for reducing the axial dimension of the clutch portion according to the first embodiment and its modification are employed, respectively, and the roller clutch B is engaged and disconnected via the armature. It is configured as follows. Note that the same operations and functions as those of the first embodiment and the modifications thereof are denoted by the same reference numerals, description thereof is omitted, and different portions and the roller clutch B will be mainly described.

  As shown in the main cross-sectional view of FIG. 11, the electromagnetic clutch unit C includes the rotor 4, the armature 5, and the electromagnetic coil 6 as in the first embodiment and its modified example. The rotor 4 and the electromagnetic coil 6 are not fixed with respect to the rotating shaft connected to the clutch B, and can rotate relative to the rotating shaft. However, the electromagnetic coil 6 is fixed to a stationary member (not shown) by a support member 3 '. The rotor 4 is integrally fixed to the outer member (outer ring) 12 of the roller clutch B, and the disc spring 7 as an elastic member is provided on the side surface of the armature 5 on the rotor 4 side so that the armature 5 is pulled away from the rotor 4. Elastic force is applied.

  The basic configuration of the roller clutch B is the same as that described in Patent Document 2, but its configuration and operation will be briefly described below. The roller clutch B is a clutch that transmits rotation between an inner member (inner ring) 10 and an outer member (outer ring) 12 via a roller 11, and the roller 11 includes a plurality of rollers (not shown) provided in a cage 13. In the example, the holder 13 is inserted and held in the pocket 11), and the retainer 13 is inserted in the holding groove at the end of the inner member 10 and does not move in the axial direction. It is provided so that it can rotate. On the outer periphery of the inner member 10, a planar cam surface extending in the tangential direction of the inner periphery within a predetermined angle range corresponding to each roller 11, and between this cam surface and the inner peripheral surface of the outer member 12. By moving the roller 11 in the formed wedge space, both the inner member 10 and the outer member 12 are engaged or disconnected.

  In this case, as shown in FIG. 12B, if the roller 11 is at the center of the cam surface, the two members do not engage (shut off) due to a slight gap with the inner peripheral surface of the outer member 12, When the roller 11 moves in either direction from the center of the cam surface and approaches the narrower wedge space, the roller 11 is sandwiched between the cam surface of the inner member 10 and the inner peripheral surface of the outer member 12 so that both members are The rotation is transmitted between the inner member 10 and the outer member 12. Further, a ring-shaped switch spring 14 is attached to a circular spring groove on the side surface of the retainer 13 opposite to the holding groove of the inner member 10, and the two tip corners (horns) of the switch spring 14 are attached. 14a and 14a are inserted into a notch 15 formed in a part of the spring groove and retainer 13, and project outward in the radial direction.

  Further, the retainer 13 is provided with protruding pieces 13R at at least two locations on the end of the spring groove, and the protruding pieces 13R are inserted into holes 13H provided at corresponding positions on the circular plate of the armature 5. . Accordingly, the armature 5 rotates integrally with the cage 13 in the rotational direction, and the movement in the axial direction is free with respect to the cage 13. Since the armature 5 is movable and rotatable in the axial direction and the rotation direction, the protruding end on the spring groove side of the inner member 10 is not provided with the protrusion 2a shown in FIG. The inner member 10 is loosely fitted. The rotating shaft 1 is inserted into the center hole 1r of the inner member 10 and is spline-fitted to rotate integrally with the inner member 10. However, the rotating shaft 1 is not shown for simplicity.

  The electromagnetic clutch as the rotation transmission device of the second embodiment configured as described above is a non-excitation operation type electromagnetic two-way clutch as in the first embodiment. As described above, in the electromagnetic clutch unit C, the armature 5 is frictionally engaged with the rotor 4 when not energized, and the armature 5 is disconnected from the rotor 4 when energized. However, in this case, if the gap between the armature 5 and the outer surface of the rotor 4 is a gap amount equal to or greater than a predetermined value (g), the attracting force of the permanent magnet 8 to the armature 5 is less than the separation force of the elastic member, and thus is not reached.

  Further, due to the phase shift of the cage 13, the roller 11 is shifted to one side of the wedge space between the cam surface and the outer peripheral surface of the outer member 12, and the roller 11 is moved to both the inner member 10 and the outer member 12. The rotation from the inner member 10 is transmitted to the outer member 12.

On the other hand, when the electromagnetic clutch unit C is energized, the magnetic coil 6 generates a magnetic flux in a direction that cancels the magnetic flux of the permanent magnet 8, so that the attractive force due to the magnetic flux difference between the permanent magnet 8 and the electromagnetic coil 6 is gap 0. Therefore, the armature 5 is pulled away from the rotor 4 to the position of the gap g ′, and the engagement of the electromagnetic clutch unit C is cut off. Even if the energization of the electromagnetic coil 6 is interrupted and the magnetic flux of the electromagnetic coil 6 is reduced to 0, there is a gap g ′ between the armature 5 and the rotor 4, so that Fm <F _K when g ′> g. The armature 5 cannot be attracted to the rotor 4 only by the magnetic force of the permanent magnet. Therefore, even when the energization to the electromagnetic coil 6 is cut off, the cut-off state of the electromagnetic clutch unit C is maintained.

Next, when it is desired to engage the roller clutch B again, the electromagnetic coil 6 is energized, and in this case, when a current is passed in the opposite direction so as to generate a magnetic flux in the same direction as the magnetic flux of the permanent magnet 8, attraction force F _M to match the permanent magnets 8 and the electromagnetic coil 6 is larger than the separating force of the elastic member be large as gap g '. For this reason, the armature 5 can be adsorbed to the rotor 4. After the adsorption, even if the energization to the electromagnetic coil 6 is interrupted, there is no gap between the armature 5 and the roller 4, so that Fm> F _{K. The} armature 5 is frictionally engaged with the rotor 4 only by the magnetic force of the permanent magnet. Continue to be. For this reason, even if it does not maintain electricity supply to the electromagnetic coil 6, the engagement of the electromagnetic clutch unit C is maintained. The magnetic force of the permanent magnet 8 is set so that the relationship between the attractive force Fm and the separation force F _K by the disc spring 7 of the elastic member is Fm <F _K , and Fm> F _K if the gap amount is g or less. And

  In the electromagnetic clutch unit C set as described above, when the armature 5 is frictionally engaged with the rotor 4 when not energized, and the rotating shaft 1 rotates and the inner member 10 rotates in this state, the rotation of the armature 5 is the roller 11. However, since the roller 11 is initially located at the center of the cam surface, the rotation is not immediately transmitted to the outer member 12. Further, since the cage 13 is fixed to the outer member 12 in the rotational direction via the armature 5 and the rotor 4, the cage 13 is also stationary with respect to the rotation if the outer member 12 is stationary. ing. However, immediately after the inner member 10 starts rotating, the cage 13 is relatively slightly out of phase with the inner member 10 in the direction opposite to the direction of rotation of the inner member 10, thereby causing the cage 13 to move. One of the two corners (horns) 14a of the switch spring that has been inserted into the notch 15 is pressed to reduce the diameter.

  For this reason, the roller 11 held by the retainer 13 is also out of phase in the direction opposite to the rotation direction of the inner member 10 and advances toward the narrower wedge space between the outer member 12 and the roller 11 with respect to both members. 11, the rotation of the inner member 10 is transmitted to the outer member 12, and the outer member 12 also starts rotating. However, when the electromagnetic coil 6 is energized, the engagement between the rotor 4 and the cage 13 is stopped when the frictional engagement of the armature 5 with the rotor 4 is interrupted, as in the first embodiment or its modification. Blocked. For this reason, the follow-up of the rotation of the outer member 12 is cut off, the switch spring 14 expands in diameter, and the roller 11 is returned to the center of the cam surface, whereby the rotation is not transmitted from the inner member 10 to the outer member 12. .

As a modification of the second embodiment, the gap amount g is any value the relationship separating force F _K of the magnetic force Fm and the elastic member of the permanent magnet 8 in the second embodiment (however, the distance the armature can be moved by the elastic member Fm> F _K even within (within range). In this case, the armature 5 and the rotor 4 are immediately frictionally engaged in the state where the energization to the electromagnetic coil 6 is cut off, and the roller clutch B is engaged if there is a difference in rotational speed between the inner member 10 and the outer member 12. It becomes. In order to set the electromagnetic clutch unit C in the idling state, the magnetic force in the direction canceling out the magnetic flux of the permanent magnet 8 and the attraction force by the permanent magnet are canceled at least below the separation force by the elastic member. It is necessary to pass a current through the electromagnetic coil 6 so as to generate the magnetic flux intensity.

As described above, if Fm> F _K regardless of the gap amount, it is necessary to continue the current flow to the electromagnetic coil 6 in order to ensure the idling state. However, unlike the case of the second embodiment, the gap amount is concerned. When the power is not supplied, the electromagnetic clutch unit C and the roller clutch B can always be engaged. Therefore, in the modified example in which Fm> F _K , when the wiring of the electromagnetic coil 6 is disconnected, or when the drive power supply fails or the voltage drops, it is necessary or desirable to engage the clutch for safety. Fits.

  The electromagnetic clutch as the rotation transmission device of the present invention has a configuration in which the dimension of the clutch portion in the axial direction is minimized, and therefore a component that requires switching between transmission and interruption of power in a power transmission path of a vehicle or the like Widely available.

(A) Main sectional view of the electromagnetic clutch of the first embodiment, (b) Partial sectional view Partial sectional side view of arrow II-II in FIG. Partial cross-sectional view taken along line III-III in FIG. Disassembled perspective view of rotor and permanent magnet Rotor side view (A) Action explanatory drawing of a clutch part, (b) Perspective view of the modification of a permanent magnet Schematic diagram showing an example of a conventional general electromagnetic clutch (a) electromagnetic coil type, (b) permanent magnet type Diagram explaining the constraint condition of the rotor ring by the number of connecting columns (A) Partial sectional view which shows the modification of the clutch part of 1st Embodiment, (b) (a) Partial sectional view of arrow BB in a figure (A) Explanatory view of the proportional action of the modified example, (b) Explanatory view of the action of this example (A) Main sectional view of electromagnetic clutch of second embodiment, (b) Explanatory drawing of action FIG. 11A is a cross-sectional view taken along line XIa-XIa in FIG. 11A, and FIG. 11B is a partial cross-sectional view taken along line XIb-XIb in FIG. (A) Electromagnetic coil clutch and (b) Non-excitation actuated electromagnetic clutch using permanent magnets in the conventional electromagnetic clutch Conventional example of non-excitation type electromagnetic clutch (a) a gap g _1, illustration of the action in the case of (b) the gap g ₂

Explanation of symbols

1 Rotating shaft (input shaft)
2 Rotating shaft (output shaft)
3 Support Member 4 Rotor 5 Armature 6 Electromagnetic Coil 7 Belleville Spring 8 Permanent Magnet 9 Connecting Column A Electromagnetic Clutch

Claims (10)

  A rotor for transmitting rotation between the rotating shafts, an armature that frictionally engages the rotor so as to move only in the axial direction and transmit the rotation, and a permanent provided in the rotor for engaging the armature with the rotor It is equipped with an electromagnet for engaging and blocking the magnet and armature, and is separated by a slit provided in the rotor to insert a permanent magnet. An electromagnetic clutch provided with a minimum number that is necessary and minimizes the total gap amount required for assembly.   The minimum number of the connecting columns is set under a condition that the mutual degree of the outer ring and the degree of restraint around the axis and the total cross-sectional area of the axial column are minimized, further determined by the number of the connecting columns. The electromagnetic clutch according to 1.   The electromagnetic clutch according to claim 1 or 2, wherein the minimum number of the connecting pillars is three.   A rotor for transmitting rotation between the rotating shafts, an armature that frictionally engages the rotor so as to move only in the axial direction and transmit the rotation, and a permanent provided in the rotor for engaging the armature with the rotor An electromagnetic clutch comprising a magnet and an electromagnet for engaging and disconnecting an armature and having a recess provided on a surface of a rotor facing a yoke of an electromagnetic coil.   4. The electromagnetic clutch according to claim 1, wherein the minimum number of connecting columns is provided, and a concave portion is provided on a surface of the rotor that faces the yoke of the electromagnet. 5.   The armature is provided with an elastic member that acts in a direction away from the rotor, and the magnetic flux density of the permanent magnet is set so that the armature is frictionally engaged with the rotor by interrupting the energization of the electromagnetic coil. The electromagnetic clutch according to claim 1, wherein:   The electromagnetic clutch according to claim 6, wherein an electromagnetic coil is provided so as to generate a magnetic flux by the electromagnetic coil in a direction to cancel the magnetic flux of the permanent magnet by energizing the electromagnetic coil. The magnetic force Fm of the permanent magnet with respect to the elastic force F _{K of the} elastic member is such that Fm> F _K when the gap between the rotor and the permanent magnet is a predetermined amount or less, and Fm <F _{K when} the gap is a predetermined amount or more. The electromagnetic clutch according to claim 6 or 7, wherein a magnetic force Fm of a permanent magnet is set to the electromagnetic clutch. The magnetic force Fm of the permanent magnet is set so that Fm> F _K with respect to the elastic force F _{K of the} elastic member, as long as the gap between the rotor and the permanent magnet is within a predetermined range. The electromagnetic clutch according to claim 6 or 7, wherein:   The electromagnetic clutch according to any one of claims 1 to 9, wherein a roller clutch having a roller as an engagement element is provided, and transmission and interruption of power between the inner member and the outer member of the roller clutch is performed with the rotor and armature of the electromagnetic clutch. An electromagnetic two-way clutch that is designed to perform transmission and disconnection.

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