JP5268309B2 - Rod linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator of a rod type, which does not exist in a conventional case. <P>SOLUTION: The rod linear actuator is provided with a cylinder rod 10 becoming a field magnetic flux generation source by giving a plurality of permanent magnets 11 and a cylinder case 30 becoming a magnetic field generation source by having coils 31. Rolling element transfer faces 32 of a plurality of bars, which extend in an axial direction, are formed on inner peripheral faces of the cylinder case 30. A spline nut 12 storing a plurality of balls 21 so that they can freely roll is fixed and installed in one cylinder rod 10. A plurality of the balls 21 roll along the rolling element transfer faces 32 formed on the inner peripheral faces of the cylinder case 30. Thus, reciprocal linear movement of the cylinder rod 10 with respect to the cylinder case 30 is guided. Fins 34 as a measures against heat dissipation are formed and thermal insulation materials 35 are installed in the cylinder case 30. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a technique for realizing an unprecedented rod-type linear actuator by combining a linear motor and a spline mechanism.

  For example, a hydraulic cylinder is generally used as an actuator for realizing an expansion / contraction operation of a mechanical device such as an injection device of an injection molding machine or a link mechanism of a construction machine. The hydraulic cylinder is a device that realizes a wide speed range and thrust range while maximizing output by changing the pressure and flow rate of the pressure oil by changing the capacity of a variable pump that is a pressure oil supply source.

  The hydraulic cylinder driven in this way is composed of a hydraulic cylinder body that performs an expansion and contraction operation, and a hydraulic pressure generator that supplies pressure oil to the hydraulic cylinder body. The hydraulic cylinder body is configured to be able to extend and contract by receiving pressure oil supplied from a hydraulic pressure generator including a hydraulic pump and a switching valve. And until now, the hydraulic cylinder main body and the hydraulic pressure generator constituting the hydraulic cylinder are arranged such that the hydraulic cylinder main body and the hydraulic pressure generator are spaced apart from each other, and supply and discharge of pressure oil between the two through the hydraulic piping, As shown in the following Patent Document 1, a configuration in which a hydraulic cylinder main body and a hydraulic pressure generator are integrated is provided.

  However, since the hydraulic cylinder requires a relatively large hydraulic pressure generator separately from the hydraulic cylinder main body, there is a problem that the manufacturing cost and the maintenance / management cost at the time of introduction become high. In addition, the hydraulic cylinder has a high output and can achieve a wide speed range and thrust range, but is not good at fine stop position control within the stroke. Could not be used. Furthermore, they also had environmental problems such as the generation of waste oil. Therefore, it has been desired to realize an electric drive device that is easy to control and clean from a hydraulic cylinder having such problems.

Japanese Utility Model Publication No. 63-164603

  By the way, the applicant manufactures and sells actuators as various power transmission mechanisms, and from the accumulation of such experience, the inventor develops an actuator having a structure combining a linear motor and a motion guide mechanism. As a result, the inventors have come up with an idea that actuators having various suitable effects that could not be realized by the prior art could be produced. In particular, if a spline device can be accommodated in a linear motor in a compact form, such a device will have very high utility in the industry.

  However, it has been extremely difficult to fit a conventional type of spline nut and spline shaft into a linear motor having a coil as a field magnetic flux generation source and a permanent magnet as a magnetic field generation source. In particular, it is technically difficult to combine a spline mechanism that repeatedly receives a rolling load from a plurality of rolling elements, such as balls, and a linear motor, which is an electrical device, and the linear motor and the spline device are simply combined. Just by using it, an actuator that can withstand practical use cannot be obtained.

  The present invention has been made in view of the existence of the above-mentioned problems, and its object is to increase the transmission efficiency of the driving force while having the advantage of the linear motor of high controllability and high rigidity. It is another object of the present invention to provide an unprecedented rod-type linear actuator that has the advantages of a spline mechanism having the above and has a compact shape.

A rod linear actuator according to the present invention includes a cylinder rod that serves as a field magnetic flux generation source by including a plurality of permanent magnets, and a cylinder case that serves as a magnetic field generation source by including a coil. In the rod linear actuator in which the cylinder rods installed in the cylinder case are reciprocally linearly movable in the axial direction by being stacked in the axial direction of the cylinder rods and fixed to each other, the inner circumference of the cylinder case A plurality of rolling element rolling surfaces extending in the axial direction are formed on the surface, and a spline nut that holds the plurality of rolling elements in a freely rolling manner is fixedly installed on the cylinder rod. The rolling elements housed in the nut are formed on the inner peripheral surface of the cylinder case. By run rolling along the body rolling run surface, the reciprocating linear motion of the cylinder rod is guided, the said coil rolling member rolling surface is placed and is formed so as not to overlap in the axial direction of the cylinder casing The cylinder rod includes: a spline nut; a field magnetic flux generating portion connected to one of the spline nuts and disposed opposite to the coil; and an action portion connected to the other of the spline nuts. configured characterized Rukoto.

  Further, in the rod linear actuator according to the present invention, the field magnetic flux generation part is made of a nonmagnetic material capable of accommodating the plurality of permanent magnets therein, and the action part is made of a metal material. can do.

  Furthermore, the rod linear actuator which concerns on this invention can install a resin bearing or a metal bearing in the location which is the axial direction edge part of the said cylinder case, and is slidably contacted with the said cylinder rod.

  In the rod linear actuator according to the present invention, it is preferable that a plurality of fins for heat dissipation are formed on an outer peripheral surface of at least a position where the coil is installed in the cylinder case.

  Furthermore, the rod linear actuator which concerns on this invention WHEREIN: A heat insulating material can be installed between the said coil and the said rolling element rolling surface in the said cylinder case.

  Furthermore, in the rod linear actuator according to the present invention, a heat insulating material can be installed on at least a side surface on the coil installation side of the spline nut fixedly installed on the cylinder rod.

  The summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  According to the present invention, while having the advantage of a linear motor with high controllability, it is possible to increase the transmission efficiency of the driving force and also have the advantage of a spline mechanism with high rigidity, and also have a compact shape. It is possible to obtain a rod type linear actuator that is not present.

  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 a longitudinal sectional front view for explaining the overall configuration of the rod linear actuator according to the present embodiment. FIG. 2 is a vertical cross-sectional side view for explaining the configuration of the linear motor portion α included in the rod linear actuator according to the present embodiment, and particularly shows a cross section taken along line AA in FIG. Furthermore, FIG. 3 is a longitudinal sectional side view for explaining the configuration of the spline mechanism portion β included in the rod linear actuator according to the present embodiment, and particularly shows a BB section in FIG. 1.

  The rod linear actuator according to the present embodiment is roughly composed of two members, a cylinder rod 10 and a cylinder case 30.

  The cylinder rod 10 includes a spline nut 12 and two shaft-shaped members, a field magnetic flux generating portion 13a and an action portion 13b, which are connected to both end surfaces of the spline nut 12. The connection between the field magnetic flux generating part 13a, the spline nut 12, and the action part 13b is realized by fastening means such as a bolt.

  The field magnetic flux generating portion 13a, which is a constituent member of the cylinder rod 10, is a member that becomes a field magnetic flux generating source by providing a plurality of permanent magnets 11 therein, and exhibits a function as a mover in the linear motor portion α. .

  Each of the plurality of permanent magnets 11 according to the present embodiment is a member having a cylindrical shape, and is stacked with respect to a cavity formed in the field flux generating portion 13a so that the cylindrical shape can be inserted in the axial direction. It is installed by. Each of the plurality of permanent magnets 11 is securely bonded and fixed with an adhesive. In the present embodiment, the plurality of permanent magnets 11 are installed such that the polarities appearing on the outer surfaces of adjacent permanent magnets are different.

  The field magnetic flux generating portion 13a that houses the plurality of permanent magnets 11 can be formed of a nonmagnetic material such as resin, aluminum, stainless steel, ceramics, or high hardness nonmagnetic free-cutting steel, and is protected from external loads. Is made. Moreover, since the field magnetic flux generation part 13a can be comprised with lightweight materials, such as resin, aluminum, and ceramics as mentioned above, it is possible to maximize the diameter of the plurality of permanent magnets 11 incorporated therein. it can. That is, as compared with the conventional linear motor, the rod linear actuator according to the present embodiment can simultaneously realize the weight reduction of the field magnetic flux generating portion 13a and the maximization of the permanent magnet 11, so that a desired output can be obtained. In this case, there is an advantage that the apparatus shape can be made compact as compared with the prior art. This advantage is also advantageous when the size of the apparatus must be the same as that of the conventional linear motor, and the diameter of the permanent magnet 11 can be made larger than that of the conventional linear motor. Even if the length is the same, the rod linear actuator according to the present embodiment can realize a higher-power linear motor than the conventional technology.

  On the other hand, the action part 13b connected to the opposite side of the field magnetic flux generation part 13a across the spline nut 12 is a member for acting on the outside to perform work, and this is made of a highly rigid metal material. Yes. That is, in the conventional rod linear actuator, since the cylinder rod is configured as a single member, the configuration cannot be selected according to the function. However, in the cylinder rod 10 according to the present embodiment, the rod portion is configured by separate members, ie, the field flux generating portion 13a and the action portion 13b. Therefore, the field flux generating portion 13a is lightweight so as to maximize the function as a linear motor. It is possible to adopt a configuration that realizes high output and high output, and it is possible to adopt a configuration that realizes high rigidity that maximizes the function as an actuator for the action portion 13b.

  Next, a specific configuration of the spline nut 12 installed by being sandwiched between the field magnetic flux generation section 13a and the action section 13b will be described with reference to FIGS. Here, FIG. 3 is a vertical cross-sectional side view for explaining the spline mechanism portion included in the rod linear actuator according to the present embodiment, and particularly shows a cross section taken along line BB in FIG.

  The spline nut 12 shown in FIGS. 1 and 3 has a plurality of rolling element rolling paths 25 therein. The plurality of rolling element rolling paths 25 are formed inside the spline nut 12 so as not to receive a load, and a pair of return paths formed at both ends of the no-load rolling element rolling path 26 ( (Not shown) and a load rolling element rolling surface 27 configured to connect a pair of return paths and allow a plurality of balls 21 to roll in a state where a part of the ball 21 is seen from the outer peripheral surface of the spline nut 12. It is configured. Therefore, the plurality of balls 21 can circulate indefinitely in the rolling element rolling path 25 constituted by the no-load rolling element rolling path 26, the pair of return paths (not shown) and the loaded rolling element rolling surface 27. ing. And the ball 21 rolling on the loaded rolling element rolling surface 27 will also roll on the rolling element rolling surface 32 formed in the inner peripheral surface side of the cylinder case 30 mentioned later. That is, since the spline nut 12 is guided along the forming direction of the rolling element rolling surface 32 formed in the cylinder case 30, a smooth reciprocating linear motion in the axial direction of the cylinder rod 10 is realized. It will be.

  As described above, the cylinder rod 10 is configured by the spline nut 12 that functions to guide the reciprocating linear motion in the axial direction, and the field magnetic flux generating portion 13a and the action portion 13b that are connected to the spline nut 12. ing. A field magnetic flux generator 13a made of a nonmagnetic material that houses a plurality of permanent magnets 11 is connected to one end of the spline nut 12 (on the right side in FIG. 1) and externally connected to the other end (on the left side in FIG. 1). The action part 13b with high rigidity for acting on and performing work is connected.

  On the other hand, the cylinder case 30 is a member having a hollow cylindrical shape as a whole, and includes a coil 31 at a position on the inner peripheral surface just opposite to the installation position of the field magnetic flux generating portion 13a constituting the cylinder rod 10. The coil 31 is a member constituting the linear motor unit α in cooperation with a plurality of permanent magnets 11 installed on the cylinder rod 10 side, and receives a supply of power from a power supply cable (not shown) to generate a magnetic field generation source. As a function.

  The coil 31 is a member configured by winding a copper wire, and by controlling the current to the coil 31, the coil 31 can generate an N pole and an S pole. As described above, since the plurality of permanent magnets 11 are installed in the cylinder rod 10 so that the polarities appearing on the outer surfaces of the adjacent permanent magnets 11 are different, the N pole is provided between the cylinder rod 10 and the coil 31. A repulsive linear motion of the cylinder rod 10 is realized by a force that pulls the S pole and the S pole, and a repulsive force that occurs between the N pole and the S pole.

  Further, a plurality of rolling element rolling surfaces 32 extending in the axial direction are formed on the inner peripheral surface of the cylinder case 30 at a position just opposite to the installation position of the spline nut 12 of the cylinder rod 10. The plurality of rolling element rolling surfaces 32 constitute a spline mechanism portion β in cooperation with the spline nut 12 installed on the cylinder rod 10 side. And as mentioned above, the cylinder 21 which conduct | electrically_connects in the cylinder case 30 when the ball | bowl 21 as the some rolling element which the spline nut 12 has on the rolling element rolling surface 32 of several strips rolls is installed. The reciprocating linear motion of the rod 10 in the axial direction is smoothly guided.

  Furthermore, the cylinder case 30 has bearings 33 for supporting the cylinder rod 10 at locations that are in sliding contact with the cylinder rod 10 (the field magnetic flux generation portion 13a and the action portion 13b) at both ends in the axial direction. . The bearing 33 can be a resin bearing or a metal bearing, and the use of the bearing 33 realizes a smooth reciprocating linear motion of the cylinder rod 10.

  By the way, in the rod linear actuator according to the present embodiment, the linear motor portion α that generates the driving force serves as a heat generation source. Therefore, by adopting a mechanism that effectively radiates heat, a highly efficient and high performance rod linear actuator is provided. Can be realized. That is, the magnetic flux is generated from the periphery of the coil 31 to the permanent magnet 11, but heat loss corresponding to the magnetic flux is generated in the cylinder case 30, and at the same time, heat is generated as current loss of the coil 31 itself. And the countermeasure against heat generation in the linear motor portion α in the rod linear actuator is indispensable for realizing the miniaturization and high performance of the linear motor.

  Therefore, in the cylinder case 30 according to the present embodiment, a plurality of heat radiation fins 34 are provided on the outer peripheral surface of the position where the coil 31 is installed. By providing a plurality of fins 34 in the vicinity of the magnetic flux generation region around the coil 31 serving as a heat generation source, that is, on the outer peripheral surface of the cylinder case 30, the contact area with the outside air is expanded, so that effective heat dissipation is realized. Become.

  In the rod linear actuator according to the present embodiment, the linear motor unit α and the spline mechanism unit β are used to prevent the occurrence of problems due to the heat generated in the linear motor unit α being transmitted to the spline mechanism unit β. It was decided to install a heat insulating material in between.

  Explaining a specific configuration, on the cylinder case 30 side of the rod linear actuator according to the present embodiment, the coil 31 and the rolling element rolling surface 32 are installed and formed so as not to overlap in the axial direction of the cylinder case 30. Furthermore, after the installation member of the coil 31 and the rolling element rolling surface 32 in the cylinder case 30 was divided, the heat insulating material 35 was installed between them. In this way, the component member of the cylinder case 30 is completely divided into the linear motor part α side and the spline mechanism part β side, and the heat insulating material 35 is installed between them, thereby ensuring reliable heat to the spline mechanism part β side. Can be cut off.

  On the other hand, on the cylinder rod 10 side, by installing a heat insulating material 15 on at least the side surface of the spline nut 12 constituting the cylinder rod 10 on the coil 31 installation side, heat transmitted from the coil 31 to the air or the permanent magnet 11 is provided. The heat transmitted from can be effectively cut off. By adopting such a configuration, in the rod linear actuator according to the present embodiment, the heat insulation to the spline mechanism portion β side is surely cut off by the effect of the heat insulating materials 15 and 35 installed at two locations. Occurrence of problems in the spline mechanism portion β due to the above is prevented, and smooth effects are realized, the efficiency of the apparatus is increased, and the apparatus life is increased.

  As described above, since the rod linear actuator according to the present embodiment has a plurality of rolling element rolling surfaces 32 formed on the inner peripheral surface of the cylinder case 30, the spline nut 12 is placed on the cylinder rod 10 side which is a drive member. It became possible to install. As a result, the cylinder rod 10 has a field magnetic flux generator 13a made of a non-magnetic material for realizing a light weight and high performance of the linear motor, and a rigidity capable of performing highly rigid work on the outside. It is possible to provide the working portion 13b made of a high metal material. Furthermore, since the effective heat radiation around the linear motor portion α can be achieved by installing the plurality of fins 34, the rod linear actuator according to this embodiment is a high-performance rod linear actuator that could not be realized by the prior art. Realized.

  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 rod linear actuator according to the present embodiment described above, by installing a plurality of permanent magnets 11 so that the polarities appearing on the outer surfaces of adjacent permanent magnets 11 are different, the current to the coil 31 is controlled. By generating an N pole and an S pole in the coil 31 and causing a pulling force between the N pole and the S pole between the cylinder rod 10 and the coil 31, and a repulsive force between the N pole and the S pole, The case where the reciprocating linear motion of the rod 10 is realized has been described.

  However, the operating principle of the rod linear actuator according to the present invention is not limited to that described above, and can be driven by the operating principle shown in FIG. Here, FIG. 4 is a schematic diagram for explaining another operating principle applicable to the rod linear actuator according to the present invention.

  In another operation principle shown in FIG. 4, the plurality of permanent magnets 11 installed on the cylinder rod 10 are arranged so that the same poles face each other, that is, the N pole and the N pole face each other, and the S pole and the S pole face each other. Are stacked. On the other hand, one set of three-phase coils that form a U, V, and W phase is the smallest installation unit, and a coil unit is formed by combining a plurality of these three-phase coils. A moving magnetic field for moving the cylinder rod 10 in the axial direction is applied to the coil 31 by flowing a three-phase current having different phases by 120 ° through the plurality of coils 31 divided into three phases of U, V, and W phases. generate. By obtaining a thrust by the moving magnetic field generated in this way, the cylinder rod 10 can perform a linear motion synchronized with the speed of the moving magnetic field.

  In the above-described embodiment, the case where the plurality of rolling elements included in the spline nut 12 are configured as the balls 21 has been described as an example. However, instead of the balls 21, rollers may be used.

  Furthermore, in the present embodiment, the case where a plurality of permanent magnets 11 are fixed with an adhesive has been described as an example. However, in the field magnetic flux generation unit 13a made of a nonmagnetic material installed so as to surround the periphery of the permanent magnets 11, A plurality of permanent magnets 11 may be fixedly installed in a stacked state by performing a caulking process or the like.

  Furthermore, in the present embodiment, the case where the field magnetic flux generating part 13a and the action part 13b connected to both sides of the spline nut 12 are configured with substantially the same diameter has been described. However, the field magnetic flux generating part 13a is described. The size of the action portion 13b may be different. In other words, the diameter and length of the field magnetic flux generating portion 13a and the action portion 13b can be arbitrarily changed. The field magnetic flux generating portion 13a can be changed according to a desired output. May be arbitrarily determined based on the size, shape, etc. of the external action object.

  Furthermore, the width dimensions and the number of installed permanent magnets 11 and coils 31 shown in FIG. 1 and FIG. 4 exemplify one form that the rod linear actuator according to the present invention can take. Therefore, the width dimension and the number of installations of the permanent magnets 11 and the coils 31 or the arrangement relationship thereof can be arbitrarily changed according to the operation performance and installation environment required for the rod linear actuator.

  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.

It is a longitudinal cross-sectional front view for demonstrating the whole structure of the rod linear actuator which concerns on this embodiment. It is a longitudinal cross-sectional side view for demonstrating the structure of the linear motor part with which the rod linear actuator which concerns on this embodiment is provided, Especially the AA cross section in FIG. 1 is shown. It is a longitudinal cross-sectional side view for demonstrating the structure of the spline mechanism part with which the rod linear actuator which concerns on this embodiment is provided, and has shown especially the BB cross section in FIG. It is a schematic diagram for demonstrating another operation principle applicable to the rod linear actuator which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Cylinder rod, 11 Permanent magnet, 12 Spline nut, 13a Field magnetic flux generation part, 13b Action part, 15 Heat insulating material, 21 Ball, 25 Rolling element rolling path, 26 Unloaded rolling element rolling path, 27 Load rolling element rolling surface , 30 Cylinder case, 31 Coil, 32 Rolling element rolling surface, 33 Bearing, 34 Fin, 35 Thermal insulation, α linear motor part, β spline mechanism part.

Claims (6)

A cylinder rod that becomes a field flux generation source by providing a plurality of permanent magnets;
A cylinder case that becomes a magnetic field generation source by providing a coil;
With
In the rod linear actuator in which the plurality of permanent magnets are stacked in the axial direction of the cylinder rod and fixed to each other so that the cylinder rod installed in the cylinder case can freely reciprocate linearly in the axial direction.
A plurality of rolling element rolling surfaces extending in the axial direction are formed on the inner peripheral surface of the cylinder case,
The cylinder rod is fixedly installed with a spline nut that accommodates a plurality of rolling elements in a freely rolling manner.
The plurality of rolling elements housed in the spline nut roll along the rolling element rolling surface formed on the inner peripheral surface of the cylinder case, whereby the reciprocating linear motion of the cylinder rod is guided. ,
The coil and the rolling element rolling surface are installed and formed so as not to overlap in the axial direction of the cylinder case,
The cylinder rod is
The spline nut;
A field flux generator connected to one of the spline nuts and disposed opposite to the coil;
An action part connected to the other of the spline nuts;
Rod linear actuator, characterized in Rukoto consists. The rod linear actuator according to claim 1 ,
The field magnetic flux generator is made of a nonmagnetic material capable of accommodating the plurality of permanent magnets therein.
The said action part is comprised with the metal material, The rod linear actuator characterized by the above-mentioned. The rod linear actuator according to claim 1 or 2 ,
A rod linear actuator, characterized in that a resin bearing or a metal bearing is installed at a position which is in an axial end portion of the cylinder case and is in sliding contact with the cylinder rod. In the rod linear actuator according to any one of claims 1 to 3 ,
A rod linear actuator, wherein a plurality of fins for heat dissipation are formed on an outer peripheral surface of at least a position where the coil is installed in the cylinder case. In the rod linear actuator according to any one of claims 1 to 4 ,
A rod linear actuator, wherein a heat insulating material is installed between the coil and the rolling element rolling surface in the cylinder case. In the rod linear actuator according to any one of claims 1 to 5 ,
A rod linear actuator, wherein a heat insulating material is installed on at least a side surface of the spline nut fixedly installed on the cylinder rod on the coil installation side.

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