Resolver arrangement structure, resolver integrated type servo motor, and set for servo motor hollow shaft mounted resolver

Abstract

To provide a system capable of mounting a resolver on a hollow shaft servo motor without extending the whole length in a shaft direction by mounting and without a diameter size being influenced by a shaft diameter.SOLUTION: In a resolver arrangement structure in a servo motor 15 having a hollow shaft 14, a resolver 10 composed of a resolver rotor 2 and a resolver stator 5 is provided on an inside 14D of the hollow shaft 14. The resolver 10 to which the present invention is applied is of an inner rotor type. A resolver rotor adapter and a resolver stator adapter are used for mounting the resolver rotor 2 and the resolver stator 5, respectively.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resolver arrangement structure, a resolver-integrated servomotor, and a set for a resolver installed in a hollow shaft of a servomotor, and more particularly to a resolver arrangement technique in a hollow shaft servomotor. [Background technology]

[0002] A solid shaft is generally used as the shaft of a servo motor. Rotation detection sensors such as resolvers and encoders are generally attached to the tip of the servo motor shaft, in which case the overall length of the motor will extend in the axial direction by the length of the sensor. On the other hand, depending on the application of the servo motor, a hollow shaft may be selected, but even in this case the attachment position is the tip of the motor shaft, so the overall length of the motor will extend in the axial direction by the length of the sensor. This will be explained using the diagram.

[0003] Fig. 7 is a perspective view of a main part showing a state where a resolver is attached in a conventional servo motor. Fig. 8 is a side cross-sectional view of a main part of the state where the resolver is attached shown in Fig. 7. As shown in these figures, the resolver is attached to a conventional servo motor 715 in the following procedure: resolver stator 75 is fixed to a motor rear cover 719 via an adapter 726, and resolver rotor 72 is directly attached to a motor shaft 714, thereby forming resolver 710.

[0004] Many patent applications have been filed for technologies for attaching resolvers to motors. For example, Patent Document 1, listed below, discloses a resolver arrangement that can shorten the motor shaft length, in which a rotating shaft having a cylindrical portion via a hub is used on the outer periphery of the central shaft, a resolver rotor is arranged on the inner periphery of the cylindrical portion of the rotating shaft, a notch is formed in the cylindrical portion, the motor rotor and the resolver rotor are connected together via a connecting portion that penetrates the notch, and a resolver stator is fixedly arranged radially inward of the resolver rotor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-110110 A "Resolver-integrated rotating electric machine and rotor core" Summary of the Invention [Problem to be solved by the invention]

[0006] As shown in Figure 7 etc., when a resolver is attached to a servo motor using the conventional method, the overall length extends in the axial direction. This is disadvantageous in terms of miniaturization of the motor and freedom of placement. In addition, a resolver larger than the shaft diameter is required, which limits the sensor selection and places great restrictions on the structure and parts selection. A method that does not have such disadvantages or restrictions is required. The same is true for the servo motor with a hollow shaft shown in the technology disclosed in the above document.

[0007] The problem that the present invention aims to solve is to provide a method for mounting a resolver to a hollow shaft servomotor, which eliminates the problems of the conventional technology and does not increase the overall axial length due to mounting, and does not affect the diameter size depending on the shaft diameter. [Means for solving the problem]

[0008] As a result of studying the above problems, the inventors of the present application came up with the idea that by locating the resolver inside the hollow shaft, it is possible to attach the resolver without increasing the overall length, and that it is possible to adopt a standard resolver instead of a resolver larger than the outer diameter of the hollow shaft. Based on this idea, the present invention was completed. That is, the invention claimed in this application, or at least the invention disclosed therein, as a means for solving the above problems, is as follows.

[0009] [1] A resolver arrangement structure in a servo motor having a hollow shaft, characterized in that a resolver consisting of a resolver rotor and a resolver stator is provided inside the hollow shaft. [2] The resolver arrangement structure according to [1], characterized in that the resolver is an inner rotor type. [3] The resolver arrangement structure according to [2], characterized in that the resolver rotor is attached to a resolver rotor adapter, and the resolver rotor adapter is fixed within the hollow shaft. [4] The resolver arrangement structure according to [3], characterized in that the resolver stator is attached to a resolver stator adapter, and the resolver stator adapter is fixed to a rear cover of a servo motor. [5] The resolver arrangement structure according to [4], characterized in that the resolver rotor adapter and the resolver stator adapter are each provided with one or more air circulation means inside and outside the hollow shaft, such as air holes that allow air to circulate inside and outside the hollow shaft.

[0010] [6] A resolver-integrated servomotor, characterized in that a resolver is attached to a hollow shaft servomotor using the resolver arrangement structure described in any one of [1], [2], [3], [4], or [5]. [7] The resolver-integrated servomotor according to [6], characterized in that a ball screw is provided inside the hollow shaft. [8] A set for constructing a resolver to be installed inside a hollow shaft of a servomotor having a hollow shaft, characterized in that it comprises a resolver rotor, a resolver rotor adapter formed to allow the resolver rotor to be attached and fixed inside the hollow shaft, a resolver stator, and a resolver stator adapter formed to allow the resolver stator to be attached and fixed to a rear cover of the servomotor. Effect of the Invention

[0011] The resolver arrangement structure, resolver-integrated servomotor, and resolver set for installation in a hollow shaft of a servomotor of the present invention are configured as described above, and therefore, according to these, the overall length of the motor does not increase axially when mounted, making it possible to miniaturize the motor and increase the freedom of mounting. In other words, while resolvers for servomotors, including those disclosed in the above documents, have traditionally been mounted on the tip of the motor shaft, according to the present invention, it is possible to mount the resolver without increasing the overall length of the motor.

[0012] According to the resolver arrangement structure, resolver-integrated servomotor, and resolver set for installation in a hollow shaft of a servomotor of the present invention, the diameter size of the resolver to be attached to the hollow shaft servomotor is not affected by the motor shaft diameter. In other words, there is no need to prepare a resolver larger than the motor shaft diameter, and a smaller resolver or a standard resolver can be used, eliminating limitations on sensor selection and restrictions on structure and part selection. [Brief description of the drawings]

[0013] [Figure 1] 1 is a side sectional view conceptually illustrating a basic configuration of a resolver arrangement structure according to the present invention; FIG. [Diagram 2] 1 is a side sectional view illustrating a method for constructing a resolver arrangement structure according to the present invention, and illustrates a method for attaching a resolver rotor. FIG. [Figure 2-2] 1 is a side sectional view illustrating a method of constructing a resolver arrangement structure according to the present invention, and illustrates a method of attaching a resolver stator. FIG. [Diagram 3] FIG. 1 is an explanatory diagram showing a configuration example of a main part of a resolver arrangement structure of the present invention having an air hole in the adapter, and is a perspective view showing a resolver section cover and a resolver stator adapter in a state after the resolver is assembled. [Figure 4] FIG. 1 is an explanatory diagram showing a configuration example of a main part of a resolver arrangement structure of the present invention having an air hole in the adapter, and is a perspective view showing a resolver stator adapter with a resolver stator fixed thereto before assembly, as viewed from the resolver rotor side. [Diagram 5]FIG. 1 is a side cross-sectional view illustrating an overview of a servomotor having a ball screw as an example of a movable body existing inside a hollow shaft. [Figure 6] FIG. 1 is a perspective view illustrating a main portion of a configuration example of a resolver arrangement structure in a servo motor having a ball screw inside a hollow shaft. [Figure 7] FIG. 11 is a perspective view of a main part showing a state in which a resolver is attached in a conventional hollow shaft servomotor. [Figure 8] 8 is a side cross-sectional view of a main part of the resolver shown in FIG. 7 in an attached state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will now be described in detail with reference to the drawings. 1 is an explanatory diagram conceptually showing the basic configuration of a resolver arrangement structure of the present invention in a cross-sectional side view of a main part. As shown in the figure, this resolver arrangement structure is a resolver arrangement structure in a servo motor 15 equipped with a hollow shaft 14, and is mainly configured such that a resolver 10 consisting of a resolver rotor 2 and a resolver stator 5 is provided inside 14D of the hollow shaft 14. As shown in the figure, the resolver 10 to which the present invention is applied is an inner rotor type.

[0015] According to the resolver arrangement structure of the present invention having such a configuration, the resolver 10 consisting of the resolver rotor 2 and the resolver stator 5 can be provided inside 14D of the hollow shaft 14 of the servo motor 15, and therefore does not extend from the tip of the hollow shaft 14. This prevents the overall axial length of the servo motor 15 from being extended, making it possible to reduce the size of the motor and increase the freedom of arrangement.

[0016] Moreover, since the resolver 10 according to the present invention is disposed inside the hollow shaft 14D, the diameter of the resolver 10 is naturally smaller than the inner diameter of the hollow shaft 14. In other words, there is no need to prepare a resolver larger than the diameter of the servo motor shaft, and a smaller resolver, a standard resolver, can be used.

[0017] 2 is a side cross-sectional view illustrating a method for constructing the resolver arrangement structure of the present invention, and illustrates a method for attaching the resolver rotor. As shown in the figure, in this resolver arrangement structure, the resolver rotor 22 is attached to the resolver rotor adapter 23, and the resolver rotor adapter 23 with the resolver rotor 22 attached is fixed inside the hollow shaft 214D, thereby forming an attachment state of the resolver rotor 22 inside the hollow shaft 214.

[0018] That is, the resolver rotor 22 of the resolver 210 according to this resolver arrangement structure rotates with the rotation of the motor shaft (hollow shaft) because the adapter 23 to which it is fixed is fixed inside 214D of the hollow shaft 214, and functions as the rotor of the resolver 210. The hollow shaft 214 is structured so that its inside 214D is provided with an in-shaft adapter fixing portion for mounting and fixing the resolver rotor adapter 23.

[0019] Fig. 2-2 is an explanatory diagram of a side cross-sectional view showing a method of constructing the resolver arrangement structure of the present invention, and shows a method of attaching a resolver stator based on Fig. 2. As shown in the figure, according to this resolver arrangement structure, the resolver stator 25 is attached to a resolver stator adapter 26, and the resolver stator adapter 26 with the resolver stator 25 attached thereto is fixed to a rear lid 219 of a servo motor 215, thereby forming an attached state of the resolver stator 25 in the hollow shaft 214. As shown in the figure, a resolver part lid 27 that covers the formed resolver 210 is fixed to the rear lid 219.

[0020] That is, the resolver stator 25 of the resolver 210 according to this resolver arrangement structure is free from the rotation of the motor shaft (hollow shaft) and is fixed to the housing side of the servo motor 215 because the adapter 26 that fixes it is fixed to the back cover 219, and functions as a stator of the resolver 210. The back cover 219 is structured to have a rear cover adapter fixing portion for attaching and fixing the resolver stator adapter 26.

[0021] Although the resolver stator 25 is fixed to the housing side of the servo motor 215, the diameter of the resolver stator 25 is formed to a size that fits inside the interior 214D of the hollow shaft 214, that is, a size smaller than the inner diameter of the hollow shaft 214. Therefore, the inner rotor type resolver 210 consisting of the resolver stator 25 and the resolver rotor 22 is disposed inside the hollow shaft 214D.

[0022] In this manner, the resolver 210 disposed in the hollow shaft of a servo motor according to the present invention is constructed by first directly attaching the resolver rotor 22 to the motor shaft 214 via the adapter 23, and then directly attaching the resolver stator 25 to the motor rear cover 219 via the adapter 26. The procedure is as follows: first, the resolver rotor 22 is attached, and then the resolver stator adapter 26 with the resolver stator already fixed thereto is attached so as to cover the resolver rotor 22, and the resolver 210 is assembled.

[0023] 3 and 4 are explanatory diagrams showing the main configuration of a configuration example of the resolver arrangement structure of the present invention having an air hole in the adapter. The former is a perspective view showing the resolver part cover and the resolver stator adapter in a see-through state after the resolver is assembled, and the latter is a perspective view showing the resolver stator adapter with the resolver stator fixed thereto before assembly, from the resolver rotor side. As shown in each figure, this resolver arrangement structure is characterized in that the resolver stator adapter 36 is provided with an air hole 38 that allows air to flow between the inside and outside of the hollow shaft. In the figures, multiple air holes 38 are provided, but the case where there is only one is not excluded. In addition, the size and shape of the air hole 38, and the number of air holes when multiple air holes are provided, are not limited.

[0024] Although not shown in Figures 3 and 4, the resolver rotor adapter may also be configured to have one or more air holes that allow air to circulate between the inside and outside of the hollow shaft. As with the air hole 38 of the resolver stator adapter 36, the size and shape of the air holes of the resolver rotor adapter, and the number of air holes if multiple are provided, are not limited. Next, the technical significance of these air holes will be explained.

[0025] 5 is an explanatory diagram of a side cross-sectional view showing an overview of a servomotor having a ball screw as an example of a movable body existing inside a hollow shaft. The servomotor 315 shown in the figure is equipped with a ball screw 40 in which a ball screw shaft 40J is housed inside the hollow shaft 314. The ball screw 40 is composed of a housing 40C, a ball screw nut 40N housed therein and rotated by the rotation of the servomotor 315, and a ball screw shaft 40J screwed in the axial direction at the center of the ball screw nut 40N.

[0026] In a normal ball screw, the shaft is rotated to operate a table connected to it, but in this ball screw 40, the ball screw nut 40N rotates with the rotation of the servo motor 315, thereby moving the ball screw shaft 40J forward and backward in the axial direction.

[0027] In the case of a mechanism equipped with a ball screw 40 connected to a servo motor 315 and in which the ball screw shaft 40J reciprocates inside the hollow shaft 314, if the ball screw shaft suddenly approaches the resolver rotor adapter, the internal pressure may increase, causing damage to the parts. The air holes provided in the resolver rotor adapter and the resolver stator adapter are a preventative measure.

[0028] 6 is a perspective explanatory diagram showing a main part of a configuration example of a resolver arrangement structure in a servo motor having a ball screw in a hollow shaft. As shown in the figure, this resolver arrangement structure can be provided with one or more air holes 38 in the resolver stator adapter 36 and one or more air holes 34 in the resolver rotor adapter 33 as a structure that allows air to flow inside and outside the hollow shaft 314. Note that the figure shows an example in which many smaller air holes 38 are provided in the resolver stator adapter 36 and a few larger air holes 34 are provided in the resolver rotor adapter 33.

[0029] With this configuration, even if the ball screw shaft 40J suddenly approaches the resolver 310, the air compressed in the interior 314D of the hollow shaft 314 easily flows out to the outside of the hollow shaft 314, so that the air pressure in the interior 314D does not increase, and damage to the parts can be effectively prevented. Note that, considering that the interior is a rotating body, it is desirable that the diameter of the air hole 38 of the resolver stator adapter 36 is a size that prevents the fingers of a worker or the like from entering.

[0030] The above describes a configuration in which the air holes 34, 38 are provided as air circulation means inside and outside the hollow shaft in the resolver arrangement structure of the present invention when a ball screw shaft that moves linearly in the axial direction is provided inside the hollow shaft, but such air circulation means inside and outside the hollow shaft is not limited to this. For example, the same effect can be obtained if each adapter has a notch or gap on the edge with appropriate specifications instead of an air hole, or if the adapter has some form that does not block the internal cross section of the hollow shaft.

[0031] The scope of the present invention also includes a resolver-integrated servomotor in which a resolver 10 or the like is attached to a hollow shaft servomotor 15 or the like by the resolver arrangement structure of the present invention having any of the above-mentioned configurations. The same applies to a resolver-integrated servomotor in which a ball screw is provided inside a hollow shaft 14 or the like.

[0032] Also within the scope of the present invention is a set for constituting a resolver 10, etc. to be installed in a hollow shaft 14, etc. of a servo motor 15, etc., which has a hollow shaft, and which comprises a resolver rotor 2, etc., a resolver rotor adapter 3, etc. formed to allow the resolver rotor 2, etc. to be attached and fixed into the hollow shaft 14, etc., a resolver stator 5, etc., and a resolver stator adapter 6, etc. formed to allow the resolver stator 5, etc. to be attached and fixed to a back cover 19, etc. of the servo motor 15, etc. [Industrial Applicability]

[0033] According to the resolver arrangement structure, resolver-integrated servomotor, and resolver set in the hollow shaft of a servomotor of the present invention, the resolver can be attached without increasing the overall length of the motor, and a standard resolver can be used without the need to prepare a resolver larger than the diameter of the motor shaft. Therefore, this invention has high industrial applicability in the fields of servomotor manufacturing and use, resolver manufacturing and use, and all related industrial and technical fields. [Explanation of symbols]

[0034] 1...Resolver shaft 2, 22, 32...Resolver rotor 5, 25, 35...Resolver stator 10, 210, 310...Resolver 14, 214, 314...Hollow shaft 14D, 24D, 34D...Inside the hollow shaft 15, 215, 315...Servo motor 15C, 315C...Servo motor housing 15R, 215R...Servo motor rotor 15S...Servo motor stator 19, 219, 319...rear lid 23, 33...Resolver rotor adapter 26, 36...Resolver stator adapter 27, 37…Resolver cover 34...Air hole (for resolver rotor adapter) 38...Air hole (for resolver stator adapter) 40…Ball screw 40C...Ball screw housing 40J...Ball screw shaft 40N...Ball screw nut 72...Resolver rotor 75...Resolver stator 710…Resolver 714…Motor shaft 715... Conventional hollow shaft servo motor 719…Motor rear cover 726…Adapter

Claims

1. A resolver arrangement structure in a servo motor having a hollow shaft, A resolver consisting of a resolver rotor and a resolver stator A resolver arrangement structure, characterized in that a resolver is provided inside the hollow shaft.

2. 2. The resolver arrangement structure according to claim 1, wherein the resolver is an inner rotor type.

3. 3. The resolver arrangement structure according to claim 2, wherein the resolver rotor is attached to a resolver rotor adapter, and the resolver rotor adapter is fixed within the hollow shaft.

4. 4. The resolver arrangement structure according to claim 3, wherein the resolver stator is attached to a resolver stator adaptor, and the resolver stator adaptor is fixed to a rear cover of a servomotor.

5. 5. The resolver arrangement structure according to claim 4, wherein the resolver rotor adapter and the resolver stator adapter are each provided with one or more air circulation means inside and outside the hollow shaft, such as air holes that allow air to circulate between the inside and the outside of the hollow shaft.

6. 6. A resolver-integrated servomotor, comprising a hollow shaft servomotor and a resolver mounted thereon by the resolver arrangement structure according to claim 1.

7. 7. The resolver-integrated servomotor according to claim 6, wherein a ball screw is provided inside the hollow shaft.

8. A set for configuring a resolver to be installed in a hollow shaft of a servo motor having a hollow shaft, A resolver rotor; a resolver rotor adapter formed to a specification that allows the resolver rotor to be attached and fixed within the hollow shaft; A resolver stator, and and a resolver stator adapter formed to allow the resolver stator to be attached and fixed to a rear cover of the servo motor.

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