JP2012072881A - Rolling element screw device with motor mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a compact rolling element screw device with a motor mechanism using a small number of part items, while solving the problem of heat generation.SOLUTION: In this rolling element screw device 10 with a motor mechanism structured by integrally combining a rolling element screw mechanism 20 with a motor mechanism 40, a permanent magnet 42 is provided in an outer peripheral surface of a nut member 31 to structure a rotor 41 in cooperation of the nut member 31 with the permanent magnet 42. A load rolling element rolling surface 32 formed in an inner peripheral surface of the nut member 31 is structured of a first load rolling element rolling surface 32a and a second load rolling element rolling surface 32b formed at a predetermined distance from each other. Further, the nut member 31 includes an elastic part 33 which applies elastic force in the parallel direction of the axial direction of the nut member 31, at a position between the first load rolling element rolling surface 32a and the second load rolling element rolling surface 32b.

Description

  The present invention relates to a rolling element screw device with a motor mechanism configured by integrally combining a rolling element screw mechanism and a motor mechanism.

  2. Description of the Related Art Conventionally, a rolling element screw device in which a nut member reciprocates along a rotation axis of a screw shaft is known as a device capable of mutually converting rotational motion and reciprocating motion. A general rolling element screw device includes a screw shaft having a spiral rolling element rolling surface on which the rolling element rolls on the outer peripheral surface, and a helical load rolling element facing the rolling element rolling surface on the inner peripheral surface. A nut member having a rolling surface, and a plurality of rolling elements interposed between the rolling element rolling surface of the screw shaft and the loaded rolling element rolling surface of the nut member, When the nut member is rotated relative to the screw shaft, the nut member can move linearly with respect to the screw shaft.

  In order to drive such a conventional rolling element screw device, it is necessary to combine with some driving force source. Conventional methods for combining the rolling element screw device and the driving force source include, for example, a method in which a hollow motor is arranged around the nut member and the nut member is rotated, and a motor and a screw shaft are arranged in parallel. However, there has been a method of transmitting the rotational driving force of the motor to the screw shaft through a power transmission member such as a timing belt.

JP-A-64-65360

  However, in the method using the hollow motor, since the heat generated by the hollow motor causes a difference in expansion amount between the nut member and the screw shaft, the driving accuracy of the rolling element screw device is lowered. It was. In addition, when the hollow motor and the nut member are separate parts, a new mechanism for mounting and rotation prevention is required, which increases the external dimensions of the device itself and increases the overall weight. There was also a problem of doing so.

  As a countermeasure against the increase in the overall weight, for example, Patent Document 1 listed above proposes a technique for integrating the rotor of the hollow motor and the nut member to realize the compactness of the entire apparatus. However, in the technique disclosed in Patent Document 1, no countermeasure is taken against the heat generation of the hollow motor, so that the nut member expands due to the heat generation of the hollow motor. And since a big preload is added to a rolling element screw apparatus (ball screw) by this expansion, in the technique disclosed by patent document 1, the cause which generate | occur | produces malfunctions, such as an early life, remains unsolved. It was.

  On the other hand, regarding the method in which the motor and screw shaft are arranged in parallel and the rotational driving force of the motor is transmitted to the screw shaft via a power transmission member such as a timing belt, the motor and the screw shaft are separated from each other. Does not exist. However, in this method, since the motor and the screw shaft are arranged in parallel, there is a problem that the external dimensions of the entire apparatus become large and a large arrangement space is required. Furthermore, in this method, since it is necessary to install a power transmission member such as a timing belt, there is a problem that the number of parts increases and a lot of manufacturing costs are required.

  The present invention has been made in view of the existence of the various problems described above, and its object is to provide a rolling element screw with a motor mechanism configured by integrally combining a rolling element screw mechanism and a motor mechanism. To provide a new rolling element screw device with a motor mechanism that has a compact outer shape and a small number of parts while maintaining the performance as a rolling element screw device by solving the heat generation problem in the device. It is in.

  The rolling element screw device with a motor mechanism according to the present invention includes a screw shaft having a spiral rolling element rolling surface on which the rolling element rolls on an outer peripheral surface, and a spiral facing the rolling element rolling surface on an inner peripheral surface. And a plurality of rolling elements interposed between the rolling element rolling surface of the screw shaft and the load rolling element rolling surface of the nut member. A rolling element screw mechanism, a rotor having a permanent magnet as a field magnetic flux generating source, and a plurality of stator coils that generate a rotating magnetic field for rotating the rotor are wound around a plurality of sets of stator cores. A rolling element screw device with a motor mechanism configured by integrally combining the rolling element screw mechanism and the motor mechanism, wherein the nut member includes: By installing the permanent magnet on the outer peripheral surface, the And the permanent magnet constitutes the rotor, and the loaded rolling element rolling surface formed on the inner peripheral surface of the nut member is formed at a predetermined distance. The load rolling element rolling surface and the second load rolling element rolling surface of the first load rolling element rolling surface and the second load rolling element rolling surface are included in the nut member. An elastic portion that exerts an elastic force in a direction parallel to the axial direction of the nut member is formed with respect to the position during the formation.

  According to the present invention, in the rolling element screw device with a motor mechanism configured by integrally combining the rolling element screw mechanism and the motor mechanism, the performance as the rolling element screw device is maintained by solving the heat generation problem. However, it is possible to provide a new rolling element screw device with a motor mechanism having a compact outer shape and a configuration with a small number of parts.

It is an external appearance perspective view of the rolling element screw device with a motor mechanism concerning this embodiment. The structural example which the rolling element screw mechanism which concerns on this embodiment can take is shown, and the external appearance side view is shown especially. The structural example which the rolling element screw mechanism which concerns on this embodiment can take is shown, and the front view is shown especially. The example of the structure which the rolling element screw mechanism which concerns on this embodiment can take is shown, and the partial longitudinal cross-section side view is shown especially. It is a figure for demonstrating the basic composition of the rolling element screw mechanism which concerns on this embodiment. It is a schematic diagram for demonstrating the drive principle of the rolling element screw mechanism which concerns on this embodiment. It is a fragmentary longitudinal cross-section for illustrating the internal structure of the rolling element screw apparatus with a motor mechanism which concerns on this embodiment, and has shown the cross section at the time of seeing in the direction along the axial direction of a screw shaft. It is a partial longitudinal cross-sectional side view which shows the example of a structure different from the rolling element screw mechanism which concerns on this embodiment illustrated in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is an external perspective view of a rolling element screw device 10 with a motor mechanism according to the present embodiment. The rolling element screw device 10 with a motor mechanism according to the present embodiment includes a rolling element screw mechanism 20 installed on the inner side and a motor mechanism 40 installed on the outer side. The rolling element screw mechanism 20 and the motor mechanism 40 are configured to be integrally combined.

  First, a specific configuration of the rolling element screw mechanism 20 according to the present embodiment will be described with reference to FIGS. Here, FIGS. 2 to 4 show configuration examples that can be taken by the rolling element screw mechanism 20 according to the present embodiment. In particular, FIG. 2 is an external side view, FIG. 3 is a front view, and FIG. Shows a partial longitudinal cross-sectional side view.

  The rolling element screw mechanism 20 according to this embodiment includes a screw shaft 21 having a spiral ball rolling groove 22 on which the ball 24 rolls on the outer peripheral surface, and a ball rolling groove 22 of the screw shaft 21 on the inner peripheral surface. A nut member 31 having spiral load ball rolling grooves 32 opposed to each other; a plurality of balls 24 interposed between the ball rolling grooves 22 of the screw shaft 21 and the load ball rolling grooves 32 of the nut member 31; , And is configured.

  As shown in FIG. 4, the ball rolling groove 22 of the screw shaft 21 is configured to have a predetermined lead L. On the other hand, the load ball rolling groove 32 formed on the inner peripheral surface of the nut member 31 includes a first load ball rolling groove 32a and a second load ball rolling groove 32b formed at a predetermined distance. It is comprised by. In the following description, the portion of the nut member 31 in which the first load ball rolling groove 32a is formed is called a first nut portion 31a, and the nut member in which the second load ball rolling groove 32b is formed. The location 31 is referred to as a second nut portion 31b. And with respect to the position between the first load ball rolling groove 32a and the second load ball rolling groove 32b, that is, the first nut portion 31a and the second nut portion in the nut member 31. An elastic portion 33 for exerting elasticity in the direction parallel to the axial direction of the nut member 31 is formed at a position between 31b.

  Each of the first nut portion 31a and the second nut portion 31b is fitted with three deflectors 35 at equal intervals in the circumferential direction (however, only one deflector 35 is shown in FIG. 4). The ball 24 that has rolled in the loaded ball rolling groove 32 (32a, 32b) passes through the return groove of the deflector 35 and is loaded into the previous loaded ball rolling groove 32 (32a, 32b). It is returned, and the same rolling route is infinitely circulated. Accordingly, the first nut portion 31a and the second nut portion 31b are each provided with three rows of balls that endlessly circulate.

  Further, seal members 26 are provided at both axial ends of the nut member 31, and the seal members 26 are separated from the gap between the axial end portion of the nut member 31 and the screw shaft 21. It plays a role of preventing foreign matter such as dust from entering the inside of the 31. Furthermore, a flange portion 27 is formed on the shaft end portion side of the first nut portion 31 a in the nut member 31. The flange portion 27 is formed with a mounting hole 28 for allowing a bolt (not shown) to pass through. By using the mounting hole 28, it is possible to mount the driving object and the nut member 31. ing.

  Next, the elastic part 33 formed between the 1st nut part 31a and the 2nd nut part 31b is demonstrated. As shown in detail in FIG. 4, the elastic portion 33 is formed as a groove over the entire circumference of the nut member 31 in the circumferential direction. As a specific forming method thereof, after grinding the load ball rolling groove 32 (32a, 32b) on the inner peripheral surface of the nut member 31, the first nut portion 31a on the inner peripheral surface of the nut member 31 and The groove 33a is formed by turning at a position between the second nut portion 31b, and then the entire nut member 31 is carburized and quenched after the outer peripheral surface side of the portion where the elastic portion 33 is to be formed is subjected to a carbon-proof treatment. After that, the charcoal-proofing treatment is peeled off, and a groove 33b is formed on the outer peripheral surface of the nut member 31 by turning.

  Thus, by turning the nut member 31 formed of one cylindrical member to form the elastic portion 33, the turning amount and angle of the grooves 33a and 33b that constitute the elastic portion 33 are arbitrarily set. As a result, the spring constant of the elastic portion 33 can be easily adjusted. Moreover, since the coaxiality of the 1st nut part 31a and the 2nd nut part 31b does not change before and after formation of the elastic part 33, it is preferable at the point which can form the high quality nut member 31. Further, since the elastic portion 33 is formed by turning from the single nut member 31, the advantage is that the strength of the elastic portion 33 is strong and the risk of the nut member 31 breaking when an impact load is applied can be minimized. have.

  Since the nut member 31 according to the present embodiment includes the elastic portion 33 as described above, it is possible to apply a suitable preload. That is, as shown in FIG. 4, the leads of the first and second load ball rolling grooves 32 (32a, 32b) are the same as the leads L of the ball rolling grooves 22 formed on the screw shaft 21. However, the distance between the first loaded ball rolling groove 32a and the second loaded ball rolling groove 32b via the elastic portion 33 is set to be smaller than the integer n times the lead L by α (nL− α). Therefore, when the nut member 31 is incorporated in the screw shaft 21, the ball 24 and the second load rolling on the first load ball rolling groove 32a even when no external force is applied to the nut member 31. Since the balls 24 rolling in the ball rolling grooves 32b are each subjected to a load that pulls in the direction of the elastic portion 33, a preload having a magnitude corresponding to the value of α is applied to the nut member 31. . In the present embodiment, the interval between the first load ball rolling groove 32a and the second load ball rolling groove 32b is (nL−α), but is larger than the integer n times the lead L by α, That is, (nL + α) may be used. In that case, since the balls 24 rolling in the first load ball rolling groove 32a and the balls 24 rolling in the second load ball rolling groove 32b are each subjected to a compressive load in the axial direction. Again, the nut member 31 is given a preload having a magnitude corresponding to the value of α.

  And the nut member 31 of this embodiment configured in this way and applied with preload is applied to a driving object such as a table via a flange-shaped flange portion 27 protruding from the outer peripheral surface of the first nut portion 31a. The elastic part 33 functions as follows although it is fixed and used with a bolt (not shown). That is, when a clearance is generated between the ball 24 and the load ball rolling groove 32 (32a, 32b) due to a lead error or a shaft diameter error of the screw shaft 21, or an excessive compressive force is applied to the ball 24. The elastic portion 33 expands and contracts to absorb the gap or to reduce the compression force. On the other hand, since the preload is applied to the nut member 31 according to the elastic force of the elastic portion 33, the function of applying a preload amount corresponding to the spring constant to the nut member 31 is obtained. Therefore, in the rolling element screw mechanism 20 according to this embodiment, even when there is a lead error or a shaft diameter error in the screw shaft 21, the nut member 31 always has a substantially constant preload due to the action of the elastic portion 33. The stable movement accuracy is exhibited.

  The specific configuration of the rolling element screw mechanism 20 according to the present embodiment has been described above. Next, the motor mechanism 40 according to the present embodiment will be described with reference to FIGS. 5 and 6 in addition to the reference drawings. Here, FIG. 5 is a diagram for explaining a basic configuration of the rolling element screw mechanism 20 according to the present embodiment. FIG. 6 is a schematic diagram for explaining the driving principle of the rolling element screw mechanism 20 according to the present embodiment.

  In the motor mechanism 40 according to the present embodiment, a rotor 41 having a plurality of permanent magnets 42 serving as a field flux generation source, and a plurality of sets of stator coils 52 of a plurality of phases that generate a rotating magnetic field that rotates the rotor 41 are fixed. And a stator 51 configured to be wound around a core core 53. The motor mechanism 40 coaxially connects a hollow cylindrical rotor 41 having a plurality of permanent magnets 42 and a stator 51 having a plurality of poles in which a stator coil 52 is wound around an iron core material (stator core) 53. Is to be arranged.

  The rotor 41 is configured by the cooperation of the nut member 31 and the permanent magnet 42, and specifically, a plurality of permanent magnets 42 are attached to the outer peripheral surface of the nut member 31 using an adhesive. It consists of pasting. The permanent magnet 42 has an N pole and an S pole so that the polarities of the magnetic poles are alternately switched in the circumferential direction of the outer peripheral surface of the nut member 31, that is, as shown in a partial diagram (b) in FIG. 5. They are arranged so that they alternate. Further, the permanent magnet 42 is installed avoiding the elastic portion 33 configured as a groove so as not to hinder the action of the elastic force exerted by the elastic portion 33. That is, the permanent magnet 42 according to the present embodiment is configured such that in the axial direction of the outer peripheral surface of the nut member 31, magnets having the same polarity of the magnetic pole are disposed with the elastic portion 33 interposed therebetween. The rotor 41 having such a configuration becomes a field magnetic flux generation source by the permanent magnet 42 and can be rotated in accordance with a rotating magnetic field generated from the stator 51.

  On the other hand, the stator 51 is obtained by winding the stator coil 52 around the teeth 53a of the stator core 53. In the case of the motor mechanism 40 illustrated in FIGS. The number of pole pairs is configured as a four pole pair. The stator 51 is configured by winding a plurality of phases of a stator coil 52 that generates a rotating magnetic field for rotating the rotor 41 around the teeth 53 a of the plurality of sets of stator cores 53.

  A more specific configuration of the stator 51 according to the present embodiment will be described. The stator 51 includes a stator core 53 and a plurality of phases (more specifically, odd-numbered phases, for example, arranged in the stator core 53). 3 phase) stator coils 52u, 52v, 52w. In the stator core 53, a plurality of teeth 53a protruding toward the inner side in the radial direction, that is, toward the rotor 41, are arranged at intervals in the circumferential direction, and further, between the teeth 53a. Slot 55 is formed. That is, the stator core 53 is formed with a plurality of slots 55 spaced apart from each other in the circumferential direction. The stator coils 52u, 52v, and 52w of the respective phases are wound around the teeth 53a through the slots 55 in a concentrated manner with short nodes. In this manner, the stator coils 52u, 52v, and 52w are wound around the teeth 53a, thereby forming a magnetic pole. The teeth 53a arranged in the circumferential direction are sequentially magnetized by passing a plurality of phases (three phases or odd phases) of alternating current through the plurality of phases (three phases or odd phases) stator coils 52u, 52v, 52w. A rotating magnetic field rotating in the circumferential direction can be formed on the teeth 53a. The rotating magnetic field formed on the teeth 53a acts on the rotor 41 from the front end surface. For example, in the example shown in FIG. 6, one pole pair is configured by three teeth 53a around which three-phase (u-phase, v-phase, and w-phase) stator coils 52u, 52v, and 52w are wound. Three-phase pole stator coils 52u, 52v, 52w are wound around each tooth 53a.

  In addition, about the stator core 53 mentioned above, the whole pole may be comprised as the single stator iron core 53, or the iron core divided | segmented for every pole is comprised, and a stator is set as an aggregate | assembly of this division | segmentation iron core. The iron core 53 may be formed.

  In the motor mechanism 40 according to the present embodiment described above, a rotating magnetic field formed on the teeth 53a acts on the rotor 41 by passing a three-phase alternating current through the three-phase stator coils 52u, 52v, and 52w. It will be. In accordance with the action of the rotating magnetic field, the permanent magnet 42 is attracted to the rotating magnetic field of the teeth 53a so that the magnetic resistance of the rotor 41 is reduced. As a result, torque (reluctance torque) acts on the rotor 41, and the rotor 41 is rotationally driven in synchronization with the rotating magnetic field formed by the stator 51.

  The rolling element screw device 10 with a motor mechanism according to the present embodiment is realized by the integrated technology of the rolling element screw mechanism 20 and the motor mechanism 40 described above. That is, even if heat from the stator coil 52, which is a heat source of the motor mechanism 40, is transmitted to the nut member 31 and a difference in expansion occurs between the nut member 31 and the screw shaft 21, in the present embodiment. Since the elastic portion 33 formed on the nut member 31 expands and contracts and absorbs an excessive amount of expansion, a substantially constant preload is always applied to the rolling element screw device 10 with a motor mechanism, and a suitable motion at all times. It is possible to maintain accuracy.

  Further, in the rolling element screw device with motor mechanism 10 according to the present embodiment, the rotor 41 is configured by attaching a plurality of permanent magnets 42 to the outer peripheral surface of the nut member 31 using an adhesive. As a result, the overall size of the apparatus is not increased, and a very compact apparatus configuration is realized. Such a configuration does not cause an increase in the number of parts, and thus is advantageous in terms of manufacturing cost.

  Further, since the plurality of permanent magnets 42 attached to the outer peripheral surface of the nut member 31 are installed avoiding the elastic portion 33 formed as a groove, the preload adjusting function exhibited by the elastic portion 33 is provided. Integration of the rolling element screw mechanism 20 and the motor mechanism 40 is realized without hindering, and this makes it possible to provide a completely new rolling element screw device 10 with a motor mechanism that has not existed in the past.

  Furthermore, since the nut member 31 is made of a metal material, it is inherently a magnetic body and can be regarded as a yoke for the permanent magnet 42. Therefore, by directly attaching a plurality of permanent magnets 42 to the outer peripheral surface of the nut member 31, the diameter of the portion of the motor mechanism 40 that functions as a motor can be obtained as compared with the case where a conventionally used hollow motor is used. Since it becomes small, it becomes possible to exhibit the suitable effect that inertia becomes small.

  In addition, about the structure employ | adopted when integrating the rolling element screw mechanism 20 and the motor mechanism 40, specifically, about the connection mechanism of the rotor 41 and the stator 51 which concern on this embodiment, FIG. It is possible to employ a configuration as exemplified in FIG. Here, FIG. 7 is a partial longitudinal cross-sectional view for illustrating the internal structure of the rolling element screw device with a motor mechanism according to the present embodiment, and a cross section when viewed in the direction along the axial direction of the screw shaft 21. Is shown.

  In the rolling element screw device 10 with a motor mechanism according to this embodiment, the rotor 41 integrated with the nut member 31 with respect to the screw shaft 21 and the stator 51 needs to be relatively rotatable. is there. At this time, the screw shaft 21 and the rotor 41 are relatively rotatable by the configuration that the rolling element screw mechanism 20 originally has. On the other hand, the stator 51 and the rotor 41 have a rolling element screw. In order to exhibit the function as a device, it is necessary to allow both members to realize a reciprocating linear motion in the axial direction of the screw shaft 21 while realizing a relative rotational motion between both members. Therefore, in the embodiment illustrated in FIG. 7, a pair of ball bearings 61 and 62 is provided between the nut member 31 configured as the rotor 41 and a member including the stator core 53 configured as the stator 51. It was decided to adopt a configuration to install. With this configuration, the rotor 41 integrated with the nut member 31 is relatively rotatable with respect to the screw shaft 21 and the stator 51, so that the two mechanisms of the rolling element screw mechanism 20 and the motor mechanism 40 are provided. It becomes possible to exhibit the function which it has suitably.

  In addition, about the flange part for connecting with drive target objects, such as a table, as shown in FIG. 7, you may make it form the new flange part 57 with respect to the stator 51, or the above-mentioned. Adopting a configuration in which the stator 51 is formed avoiding the flange portion 27 so that the flange-like flange portion 27 protruding from the outer peripheral surface of the first nut portion 31a of the nut member 31 can be used as it is. Also good.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment.

  For example, in the above-described embodiment, the case where the ball 24 is used as the rolling element has been described as an example. However, any form such as a roller or a roller can be used as the rolling element. Depending on the type of rolling element, the rolling element rolling surface of the screw shaft and the loaded rolling element rolling surface of the nut member can be formed into a groove shape or a surface shape.

  Moreover, about the structure of the rolling element screw mechanism 20 and the motor mechanism 40 which were mentioned above, it is possible to employ | adopt various deformation | transformation forms in the range which can implement | achieve the effect which the embodiment mentioned above can exhibit.

  For example, in the rotor 41 of the above-described embodiment, the plurality of permanent magnets 42 are attached to the outer peripheral surface of the nut member 31 using an adhesive, but there are various methods for installing the permanent magnets. The mounting groove may be formed by performing grooving on the outer peripheral surface of the nut member 31, and the permanent magnet 42 may be fitted into the mounting groove.

  Further, the number of permanent magnets 42 included in the motor mechanism 40 and the number of poles of the stator 51 can be appropriately changed.

  Furthermore, although the elastic part 33 of embodiment mentioned above was formed of the groove | channel 33a formed in the inner peripheral surface of the nut member 31, and the groove | channel 33b formed in the outer peripheral surface of the nut member 31, it concerns on this invention. About the shape of an elastic part, it is possible to employ | adopt all the deformation | transformation forms in the range which exhibits the effect similar to the elastic part 33 mentioned above.

  For example, you may make it form the elastic part of this invention by forming a groove | channel only in one of the internal peripheral surface or outer peripheral surface of a nut member. Further, a convex shape that protrudes outward from the peripheral surface is formed on one side of the inner peripheral surface or the outer peripheral surface of the nut member, and the outer peripheral surface or the inner peripheral surface of the nut member corresponding to the convex shape is formed. You may make it form the elastic part by the combination of a convex shape and a groove | channel by forming a groove | channel on the other side. Furthermore, although the elastic part 33 of embodiment mentioned above formed the groove | channel one each with respect to the inner peripheral surface and outer peripheral surface of the nut member 31, about the number of grooves, it can increase arbitrarily. Is possible.

  Moreover, the elastic part of this invention is not comprised only by the combination of 1 or more groove | channels or a groove | channel and a convex part shape. For example, by making a spiral hole in the central part of the nut member configured as one member, a coil shape is formed in the central part of the nut member, and by using the elastic force acting by this coil shape Another elastic part according to the present invention may be configured.

  The various configuration examples that can be taken by the elastic portion according to the present invention have been described above. However, the elastic portion described above is applied to a nut member configured as one member. However, the nut member according to the present invention may be configured by combining a plurality of members configured separately. FIG. 8 shows an example of such a configuration.

  Here, FIG. 8 is a partial vertical cross-sectional side view showing a configuration example different from the rolling element screw mechanism according to the present embodiment illustrated in FIG. 4, and the rolling element screw mechanism 20 shown in FIG. 8. The first nut portion 31a 'and the second nut portion 31b' are configured as two divided members as in the case of ', and an elastic body is provided between the first nut portion 31a' and the second nut portion 31b '. The two disc springs 83a and 83b are sandwiched and integrated by projection welding to constitute an elastic portion 83 that exerts an elastic force in a direction parallel to the axial direction of the nut member 31 ′. Good. For a nut member 31 ′ constituted by a first nut portion 31a ′ and a second nut portion 31b ′ which are two divided members, and an elastic portion 83 comprising two disc springs 83a and 83b connecting these members. Thus, by installing the permanent magnet 42 while avoiding the elastic portion 83, it is possible to realize the rolling element screw mechanism 20 ′ integrated with the rotor capable of exhibiting the same effect as the above-described embodiment. It becomes. In addition, about the spring constant of the elastic part 83, it can adjust freely by changing suitably the elastic force of the two disc springs 83a and 83b.

  Furthermore, in the configuration example shown in FIG. 8, the elastic part 83 installed between the first nut part 31 a ′ and the second nut part 31 b ′ divided into two parts is provided with two disc springs 83 a. However, the elastic body that can be used for the elastic portion 83 is not limited to the disc springs 83a and 83b. Any other elastic body capable of exerting an elastic force can be adopted for the elastic portion of the present invention.

  It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Rolling body screw apparatus with motor mechanism, 20, 20 'Rolling body screw mechanism, 21 Screw shaft, 22 Ball rolling groove, 24 Ball, 26 Seal member, 27 Flange part, 28 Mounting hole, 31, 31' Nut member, 31a, 31a ′ first nut portion, 31b, 31b ′ second nut portion, 32 loaded ball rolling groove, 32a first loaded ball rolling groove, 32b second loaded ball rolling groove, 33 elastic portion, 33a , 33b Groove, 35 Deflector, 40 Motor mechanism, 41 Rotor, 42 Permanent magnet, 51 Stator, 52, 52u, 52v, 52w Stator coil, 53 Stator iron core, 53a Teeth, 55 slots, 57 Flange, 61 , 62 Ball bearing, 83 Elastic part, 83a, 83b Belleville spring.

Claims (4)

A screw shaft having a spiral rolling element rolling surface on which the rolling element rolls on the outer peripheral surface, and a nut member having a spiral load rolling element rolling surface facing the rolling element rolling surface on the inner peripheral surface; A rolling element screw mechanism comprising: a plurality of rolling elements interposed between the rolling element rolling surface of the screw shaft and the load rolling element rolling surface of the nut member;
A rotor having a permanent magnet as a field magnetic flux generation source, and a stator configured by winding a plurality of stator coils that generate a rotating magnetic field for rotating the rotor around a set of stator cores. A motor mechanism comprising:
With
In the rolling element screw device with a motor mechanism configured by integrally combining the rolling element screw mechanism and the motor mechanism,
By installing the permanent magnet with respect to the outer peripheral surface of the nut member, the nut member and the permanent magnet cooperate to constitute the rotor,
The loaded rolling element rolling surface formed on the inner peripheral surface of the nut member is formed by a first loaded rolling element rolling surface and a second loaded rolling element rolling surface formed at a predetermined distance. Configured, and
The nut member has an elastic force in a direction parallel to the axial direction of the nut member with respect to a position between the first load rolling element rolling surface and the second load rolling element rolling surface. A rolling element screw device with a motor mechanism, wherein an elastic part is formed. In the rolling element screw device with a motor mechanism according to claim 1,
The rolling member screw device with a motor mechanism, wherein the nut member formed with the elastic portion is composed of one member. In the rolling element screw device with a motor mechanism according to claim 1,
The nut member is
A first nut portion on which the first loaded rolling element rolling surface is formed;
A second nut portion on which the second load rolling element rolling surface formed separately from the first nut portion is formed;
An elastic portion made of an elastic body sandwiched between the first nut portion and the second nut portion;
A rolling element screw device with a motor mechanism, comprising: In the rolling element screw device with a motor mechanism given in any 1 paragraph of Claims 1-3,
The said permanent magnet is installed avoiding the said elastic part, The rolling element screw apparatus with a motor mechanism characterized by the above-mentioned.

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