JP2007043878A - Linear motor cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel and compact cylinder exhibiting high driving force transmission efficiency while having the advantage of an electric cylinder, i.e. high controllability. <P>SOLUTION: The linear motor cylinder includes a hollow tubular member 10, and a cylinder rod 30 arranged reciprocatively for the tubular member 10. The cylinder rod 30 becomes a field flux generation source when it is provided with a plurality of permanent magnets 32 in the rod, and further provided with a spline groove 34 in the outer circumferential surface of the rod. The tubular member 10 comprises a stator coil 12 generating a magnetic field causing reciprocal linear motion of the cylinder rod 30 at a position corresponding to the plurality of permanent magnets 32, and a spline outer tube 14 for guiding reciprocal linear motion of the cylinder rod 30 at a position corresponding to the spline groove 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a linear motor cylinder device, and more particularly to a technique for realizing an unprecedented cylinder device 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. In this hydraulic cylinder, the pressure and flow rate of the pressure oil are changed by changing the capacity of the variable pump that is a pressure oil supply source, and a wide speed range and thrust range are realized while maximizing the output.

  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, A configuration in which a hydraulic cylinder body and a hydraulic pressure generator are integrally formed is provided (for example, see Patent Document 1 below).

  However, since the hydraulic cylinder requires a relatively large hydraulic pressure generator separately from the hydraulic cylinder body as described above, there is a problem that the manufacturing cost and the maintenance / management cost at the time of introduction become high. It was. 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, various techniques have been devised to replace the hydraulic cylinder having such problems with an electric cylinder using a motor that is easy to control and clean. According to such an electric cylinder, advantages that the hydraulic cylinder does not have, for example, in terms of cost and control, installation conditions, environmental problems, and the like can be exhibited (for example, see Patent Documents 2 and 3 below).

Japanese Utility Model Publication No. 63-164603 JP-A-9-271154 JP 2003-184981 A

  However, the electric cylinders provided up to now have a problem that the transmission efficiency of the motor driving force is very poor because a mechanism for converting the rotational motion by the motor or the like into a linear motion is necessarily required. In addition, although the device size has been improved compared to the hydraulic cylinder, there is still room for downsizing due to the need to connect the motor etc. to the conversion mechanism, further minimizing the device size. Was desired.

  The present invention has been made in view of the existence of such problems, and provides a new cylinder device that has the advantage of an electric cylinder of high controllability and is compact and has high transmission efficiency of driving force. It is the purpose.

  A linear motor cylinder device according to the present invention includes a hollow cylindrical cylindrical member, and a cylinder rod installed so as to be movable forward and backward with respect to the cylindrical member, and the cylinder rod includes a plurality of rods inside the rod. By providing a permanent magnet, it becomes a field magnetic flux generating source, and has a spline groove on the outer peripheral surface of the rod, and the cylindrical member has a position corresponding to the plurality of permanent magnets for a magnetic field for reciprocating linear movement of the cylinder rod And a spline outer cylinder for guiding the reciprocating linear motion of the cylinder rod at a position corresponding to the spline groove.

  In the linear motor cylinder device according to the present invention, the plurality of permanent magnets are stacked in the axial direction of the cylinder rod and fixed to each other, and are arranged so that the polarities appearing on the outer surfaces of adjacent permanent magnets are different. Can be.

  In the linear motor cylinder device according to the present invention, it is preferable that the permanent magnet and the spline groove are installed so as not to overlap in the circumferential direction of the rod.

  Furthermore, in the linear motor cylinder device according to the present invention, the plurality of permanent magnets are divided into a plurality of parts in the circumferential direction of the cylinder rod, and the stator coil corresponds to a permanent magnet divided in the circumferential direction. A plurality of permanent magnets and the spline grooves may be installed so as not to overlap in the circumferential direction of the rod and to overlap in the axial direction of the rod.

  Furthermore, in the linear motor cylinder device according to the present invention, the cylinder rod on which the plurality of permanent magnets are installed can be made of a nonmagnetic material.

  Furthermore, in the linear motor cylinder device according to the present invention, the nonmagnetic material can be at least one of stainless steel, ceramics, and high hardness nonmagnetic free-cutting steel.

  Moreover, the linear motor cylinder apparatus which concerns on this invention WHEREIN: The said stator coil shall be installed by being wound around the core iron core which the said cylinder rod has.

  Furthermore, it is preferable that a linear scale for controlling the reciprocating linear motion of the cylinder rod is installed in the linear motor cylinder device according to the present invention.

  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, as a driving source of the cylinder device, a configuration capable of exerting a driving force called a linear motor by linear motion is adopted, so that the transmission efficiency is very high and the controllability is equal to or better than that of an electric cylinder. Can be provided. In addition, the use of a linear motor can provide a cylinder device that achieves a compactness that cannot be achieved by a conventional electric cylinder.

  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. .

[First Embodiment]
The linear motor cylinder device according to the first embodiment will be described with reference to FIGS. 1, 2, and 3. Here, FIG. 1 is an external perspective view showing the overall configuration of the linear motor cylinder device according to the first embodiment, and a part of the outer constituent member is shown by a broken line for explanation of the internal structure. FIG. 2 is a longitudinal sectional side view of the linear motor cylinder device according to the first embodiment, and FIG. 3 is a sectional view taken along the line AA in FIG.

  The linear motor cylinder device according to the first embodiment includes a cylindrical member 10 having a hollow cylindrical shape and a cylinder rod 30 that is installed so as to be movable forward and backward with respect to the cylindrical member.

  A cylinder rod 30 serving as an action part of the linear motor cylinder device includes a plurality of permanent magnets 32 inside the rod. These permanent magnets 32 are stacked in the axial direction of the cylinder rod 30 and fixed to each other, and are arranged so that the polarities appearing on the outer surfaces of adjacent permanent magnets are different. Therefore, the cylinder rod 30 becomes a field flux generation source by the effect of the plurality of permanent magnets 32, and can function as a mover in the linear motor. Each of the plurality of permanent magnets 32 according to the first embodiment is a member having a columnar shape, and a cavity formed in the cylinder rod 30 so that the columnar shape can be inserted in the axial direction. And are installed by stacking.

  Further, a spline groove 34 is formed on the rod outer peripheral surface of the cylinder rod 30, and a stable reciprocating linear motion of the cylinder rod 30 is achieved by cooperating with a spline outer cylinder 14 on the cylindrical member 10 side described later. The function to guide will be demonstrated. The spline groove 34 is formed at a position that does not overlap the permanent magnet 32 in the circumferential direction of the rod so as not to interfere with the strength of the cylinder rod 30 and the field magnetic flux generated by the permanent magnet 32. Further, the permanent magnet 32 and the spline groove 34 are installed so as not to overlap in the axial direction of the rod. Therefore, the length of the cylinder rod 30 according to the first embodiment is required to be at least twice as long as the length of the permanent magnet 32 installation location that becomes a stroke.

  Furthermore, the constituent material of the cylinder rod 30 that houses and installs the permanent magnet 32 is preferably a non-magnetic material. This is because if the cylinder rod 30 is made of a magnetic material, it will be difficult to transmit the field magnetic flux generated by the permanent magnet 32 and affect the rod operation. By forming the magnetic material, stable field flux generation is realized. Examples of nonmagnetic materials suitable for use in the cylinder rod 30 include stainless steel, ceramics, and high hardness nonmagnetic free-cutting steel. In particular, high-hardness nonmagnetic free-cutting steel has high strength compared to other materials, and is suitable for use as a cylinder rod 30 that serves as a working part and performs work as a cylinder device. As a specific steel type, Hitachi Metals Co., Ltd. HPM75, etc., having a hardness at the time of use of about 40 to 45 in HRC (Rockwell hardness) can be employed.

  On the other hand, the cylindrical member 10 constituting the outline of the linear motor cylinder device includes a stator coil 12 for generating a magnetic field for reciprocating linear movement of the cylinder rod 30 at positions corresponding to a plurality of permanent magnets, and the cylinder rod 30. A spline outer cylinder 14 for guiding the reciprocating linear motion at a position corresponding to the spline groove 34.

  The stator coil 12 is a member configured by winding a coil, and can control the current to the stator coil 12 to generate an N pole and an S pole in the coil. Since the cylinder rod 30 is provided with a plurality of permanent magnets 32 so that the polarities appearing on the outer surfaces of the adjacent permanent magnets are different, the N pole and the S pole between the cylinder rod 30 and the stator coil 12 are arranged. The pulling force and the repulsive force between the N poles and the S poles occur, and the reciprocating linear motion of the cylinder rod 30 is realized.

  The spline outer cylinder 14 is a member that is fixedly installed on one end side of the cylindrical member 10 having a hollow cylindrical shape, and is a member that includes a flange 13 for fixing and installing the linear motor cylinder device according to the first embodiment. is there. The spline outer cylinder 14 has rolling grooves corresponding to the spline grooves 34, and a plurality of protrusions extending in the direction in which the spline grooves 34 extend are formed in these rolling grooves. Then, a load rolling path is formed between the rolling groove formed in the spline outer cylinder 14 and the spline groove 34 formed in the cylinder rod 30, and the load rolling path is released from the load next to the load rolling path. A no-load return path through which the ball 15 is moved is formed. The spline outer cylinder 14 incorporates a cage 16 that aligns and holds a plurality of balls 15 in a circuit shape. A plurality of balls 15 are installed so as to roll freely between the rolling groove of the spline outer cylinder 14 and the spline groove 34 of the cylinder rod 30 so as to circulate infinitely through the no-load return passage. Thus, stable reciprocating linear motion of the cylinder rod 30 with respect to the spline outer cylinder 14 (that is, the cylindrical member 10) is realized.

  Although the operation of the linear motor cylinder device according to the first embodiment is realized by the configuration described above, the linear motor cylinder device according to the first embodiment further performs the reciprocating linear motion of the cylinder rod 30. A linear scale 40 for control is installed.

  A linear scale 40 illustrated in FIGS. 1 and 2 is an optical linear scale, and has a main scale 41 having a scale perpendicular to the moving direction of the cylinder rod 30, a light emitting unit and a light receiving unit that are installed opposite to the main scale 41. And a read head 42 having a portion. Accordingly, since the main scale 41 also moves as the cylinder rod 30 moves, the reading head 42 can read the scale engraved on the main scale 41 and can grasp the amount of movement of the cylinder rod 30. Become.

  Since the linear motor cylinder device according to the first embodiment has the above-described configuration, the transmission efficiency is very high and controllability equivalent to or higher than that of the electric cylinder can be exhibited. In addition, by adopting a linear motor, it is possible to achieve a level of compactness that cannot be achieved with a conventional electric cylinder.

[Second Embodiment]
In the first embodiment, the linear motor cylinder device that has achieved a level of compactness that cannot be achieved by the conventional electric cylinder has been described. However, the linear motor cylinder device according to the second embodiment to be described below is further improved. It has a form to achieve compactness. Accordingly, a linear motor cylinder device according to the second embodiment will be described with reference to FIGS. 4, 5, and 6. Here, FIG. 4 is an external perspective view showing the entire configuration of the linear motor cylinder device according to the second embodiment, and a part of the outer constituent member is shown by a broken line for explanation of the internal structure. FIG. 5 is a longitudinal sectional side view of the linear motor cylinder device according to the second embodiment, and FIG. 6 is a sectional view showing a BB section in FIG. Note that members that are the same as or similar to the members described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  A characteristic feature of the linear motor cylinder device according to the second embodiment is that a plurality of permanent magnets 52 are divided into a plurality of parts in the circumferential direction of the cylinder rod 30 (in FIG. 4 to FIG. 6, it is divided into three parts). It is mentioned that. The permanent magnet 52 and the spline groove 34 are arranged so as not to overlap in the circumferential direction of the rod, as in the first embodiment, but in the second embodiment, the spline groove 34 is divided. The permanent magnet 52 and the spline groove 34 can be installed so as to overlap in the axial direction of the rod.

  That is, in the linear motor cylinder device according to the first embodiment, the spline groove 34 is installed so as not to overlap in the axial direction of the rod so as not to interfere with the field magnetic flux generated by the permanent magnet 32. In the linear motor cylinder device according to the second embodiment, the permanent magnet 52 is divided in the circumferential direction, and the spline groove 34 is positioned in the gap position of the magnet. Even if the permanent magnets 52 are overlapped and set, a configuration in which interference with the field flux does not occur can be realized. By configuring in this way, the positions of the spline groove 34 and the permanent magnet 52 can be overlapped in the axial direction of the rod. Therefore, if the stroke is the same as that of the linear motor cylinder device according to the first embodiment, the cylinder rod is shorter. If the cylinder rod 30 has the same length as that of the linear motor cylinder device according to the first embodiment, a linear motor cylinder device that realizes a larger stroke can be obtained.

  In the linear motor cylinder device according to the second embodiment, the number corresponding to the number of magnet divisions (three in FIG. 4 to FIG. 6) is located at the position corresponding to the permanent magnet 52 divided in the circumferential direction of the rod. ) Stator coil 53 is installed. Further, the stator coil 53 is installed by being wound around a core iron core 55 provided inside the cylinder rod 30. By configuring the stator coil 53 in this way, it is possible to reinforce the magnetic force with respect to each permanent magnet 52, so that it is possible to eliminate the influence caused by dividing the magnet, and the linear according to the first embodiment. A compact linear motor cylinder device having an action force equal to or greater than that of the motor cylinder device can be 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. In each of the above-described embodiments, the case where the optical linear scale 40 configured by the main scale 41 and the reading head 42 is employed has been described as an example. For example, the permanent magnets 32 and 52 associated with the movement of the rod are described. It is also possible to employ a magnetic linear scale that can grasp the amount of movement of the cylinder rod 30 by reading the change in magnetic flux. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

1 is an external perspective view showing an overall configuration of a linear motor cylinder device according to a first embodiment. It is a longitudinal cross-sectional side view of the linear motor cylinder apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the AA cross section in FIG. It is an external appearance perspective view which shows the whole linear motor cylinder apparatus structure which concerns on 2nd Embodiment. It is a longitudinal cross-sectional side view of the linear motor cylinder apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the BB cross section in FIG.

Explanation of symbols

  10 cylindrical member, 12 stator coil, 13 flange, 14 spline outer cylinder, 15 ball, 16 cage, 30 cylinder rod, 32 permanent magnet, 34 spline groove, 40 linear scale, 41 main scale, 42 read head, 52 Permanent magnet, 53 stator coil, 55 core iron core.

Claims (8)

A hollow cylindrical tubular member;
A cylinder rod installed to be movable back and forth with respect to the tubular member;
Have
The cylinder rod serves as a field magnetic flux generation source by including a plurality of permanent magnets inside the rod, and includes a spline groove on the outer peripheral surface of the rod.
The cylindrical member is
A stator coil for generating a magnetic field for reciprocating linear movement of the cylinder rod at a position corresponding to the plurality of permanent magnets;
A spline outer cylinder for guiding the reciprocating linear motion of the cylinder rod at a position corresponding to the spline groove;
A linear motor cylinder device comprising: In the linear motor cylinder device according to claim 1,
The linear motor cylinder device characterized in that the plurality of permanent magnets are stacked in the axial direction of the cylinder rod and fixed to each other, and are arranged so that polarities appearing on the outer surfaces of adjacent permanent magnets are different. . In the linear motor cylinder device according to claim 1 or 2,
The linear motor cylinder device, wherein the permanent magnet and the spline groove are installed so as not to overlap in a circumferential direction of the rod. In the linear motor cylinder device according to claim 2 or 3,
The plurality of permanent magnets are divided into a plurality in the circumferential direction of the cylinder rod,
A plurality of the stator coils are installed corresponding to the permanent magnets divided in the circumferential direction, and
The linear motor cylinder device, wherein the permanent magnet and the spline groove are installed so as not to overlap in the circumferential direction of the rod and in the axial direction of the rod. In the linear motor cylinder device according to any one of claims 1 to 4,
The linear motor cylinder device, wherein the cylinder rod on which the plurality of permanent magnets are installed is made of a nonmagnetic material. In the linear motor cylinder device according to claim 5,
The linear motor cylinder device according to claim 1, wherein the nonmagnetic material is at least one of stainless steel, ceramics, and high hardness nonmagnetic free-cutting steel. In the linear motor cylinder device according to any one of claims 1 to 6,
The linear motor cylinder device according to claim 1, wherein the stator coil is wound around a core iron core of the cylinder rod. In the linear motor cylinder device according to any one of claims 1 to 7,
A linear motor cylinder device, wherein a linear scale for controlling the reciprocating linear motion of the cylinder rod is installed.

Images