Motor drive unit

Abstract

A motor drive device is provided that has a structure that minimizes the number of parts and that makes it difficult for heat from a regenerative resistor to be transmitted to circuit drive components. The motor drive device includes drive circuit components for driving the motor, a regenerative resistor for consuming regenerative power from the motor, and a flange to which the drive circuit components and the regenerative resistor are attached, and the surface of the flange facing the regenerative resistor has at least one stepped portion that comes into contact with the regenerative resistor and is made of the same material as the flange.

Description

Technical Field

[0001] The present disclosure relates to a motor drive device.

Background Art

[0002] In general machine tools and the like, even when the power supply is cut off, the motors that drive the respective axes of the machine tool do not stop immediately and continue to rotate for a certain period of time. If the motor is rotating when the machine tool is not in a controlled state, there is a possibility that the machine tool or the workpiece to be machined may be damaged. Therefore, in a motor drive device that drives a motor, a regenerative resistor that converts the rotational energy of the motor into heat and consumes it may be provided.

[0003] Since the regenerative resistor may become very hot, techniques are known to make it difficult for the heat of the regenerative resistor to be transmitted to other components of the motor drive device, or to actively release the heat of the regenerative resistor to the outside using means such as heat sinks and heat radiating fins.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Some conventional motor drive devices have a structure in which the heat of the regenerative resistor easily spreads to drive circuit components such as power elements. Since the upper limit temperature of use of a power element is lower than that of the regenerative resistor, it may be necessary to lower the output of the power element so that the temperature of the power element is below the upper limit temperature of use. However, in such a case, there is a problem that the performance of the motor drive device deteriorates.

[0006] On the other hand, there are known structures in which heat sinks or other means are attached to the regenerative resistor to actively transfer heat from the regenerative resistor to other parts. However, such structures increase the number of parts, leading to increased costs for the motor drive system. Therefore, a motor drive system is desired that has a structure that minimizes the number of parts while preventing heat from the regenerative resistor from being transferred to the circuit drive components. [Means for solving the problem]

[0007] One aspect of the present disclosure is a motor drive device comprising a drive circuit component for driving a motor, a regenerative resistor for consuming regenerative power from the motor, and a flange to which the drive circuit component and the regenerative resistor are attached, wherein the surface of the flange facing the regenerative resistor has at least one stepped portion formed of the same material as the flange that contacts the regenerative resistor.

[0008] Another aspect of the present disclosure is a motor drive device comprising a drive circuit component for driving a motor, a regenerative resistor for consuming regenerative power from the motor, and a flange to which the drive circuit component and the regenerative resistor are mounted, wherein the opposing surfaces of the regenerative resistor and the surfaces of the flange do not come into contact with each other. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view of a motor drive device according to the first embodiment. [Figure 2] Figure 1 is a plan view of the flange of the motor drive unit. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] Figure 1 is a perspective view of the flange of the motor drive unit. [Figure 5] This figure shows an example of the installation procedure for a regenerative resistor on a flange. [Figure 6] Figure 5 is a magnified view of the regenerative resistance. [Figure 7]It is a plan view showing a state where a regenerative resistor is attached to a flange. [Figure 8] It is a plan view showing an example of the structure of a flange according to the second embodiment. [Figure 9] It is a plan view showing an example of the structure of a regenerative resistor according to the third embodiment. [Figure 10] It is a partially enlarged view of the regenerative resistor in FIG. 9. [Figure 11] It is a view showing an example of the operation of attaching a regenerative resistor to a flange. [Figure 12] It is a plan view showing a state where a regenerative resistor is attached to a flange. [Figure 13] It is a plan view showing an example of the structure of a regenerative resistor according to the fourth embodiment. [Figure 14] It is a partially enlarged view of the regenerative resistor in FIG. 13. [Figure 15] It is a plan view showing an example of the structure of a flange according to the fourth embodiment. [Figure 16] It is a partially enlarged view of the flange in FIG. 15. [Figure 17] It is a view showing an example of the operation of attaching a regenerative resistor to a flange. [Figure 18] It is a plan view showing a state where a regenerative resistor is attached to a flange. [Figure 19] It is a view of the configuration in FIG. 18 as seen from the side. [Figure 20] It is a partially enlarged view of FIG. 19. [Figure 21] It is a plan view showing a flange and a regenerative resistor according to the fifth embodiment. [Figure 22] It is a cross-sectional view taken along line XXII-XXII of FIG. 21. [Figure 23] It is a partially enlarged view of FIG. 22. [Figure 24] It is a cross-sectional view of a flange and a regenerative resistor according to the comparative example. [Figure 25] It is a partially enlarged view of FIG. 24.

Mode for Carrying Out the Invention

[0010] (First Embodiment) Figure 1 is a schematic diagram showing the configuration of a motor drive device 10 according to the first embodiment, and Figure 2 is a plan view of the flange 16 of the motor drive device 10. The motor drive device 10 includes a drive circuit component 12 for driving a motor 2, a regenerative resistor 14 for consuming regenerative power from the motor 2, and a flange 16 to which the drive circuit component 12 and the regenerative resistor 14 are attached. The motor 2 is, for example, a motor such as a servo motor that drives each axis of a machine tool or robot, and the drive circuit component 12 is, for example, a power element.

[0011] The regenerative resistor 14 is mounted facing a mounting surface 18 that is different from the side of the flange 16 to which the power element 12 is attached. As shown in Figure 2, the mounting surface 18 of the flange 16 has at least one stepped portion 20 in which fixing holes 22 for fixing the regenerative resistor 14 are formed. The stepped portion 20 is integrally formed from the same material as the flange 16.

[0012] In this embodiment, the fixing holes 22 for the regenerative resistor 14, which are an essential means for fixing the regenerative resistor 14, are provided in the stepped portion 20 formed from the same material as the flange 16. As a result, the contact area between the regenerative resistor 14 and the flange 16 can be significantly reduced without increasing the number of parts. Consequently, even if the regenerative resistor 14 generates heat, the amount of heat conducted to the flange 16 is greatly reduced, thereby suppressing the temperature rise of the power element 12 and enabling higher output as a motor drive device.

[0013] Preferably, the mounting surface 18 has at least one projection 24 that contacts the regenerative resistor 14, in addition to the stepped portion 20. As a result, as shown in cross-sectional figure 3, the regenerative resistor 14 will contact the top portion 26 of the projection 24, further reducing the contact area between the regenerative resistor 14 and the flange 16.

[0014] Figure 4 is a perspective view of the flange 16, and Figure 5 shows an example of the mounting operation of the regenerative resistor 14 to the flange 16. The flange 16 has an opening or recess 28 on the side opposite to the side with the stepped portion 20 in its longitudinal direction. On the other hand, as shown in Figure 6, the regenerative resistor 14 has a hook mechanism 32 that can engage with the opening 28, and in the illustrated example, it has two hooks 32a and 32b of different sizes. The regenerative resistor 14 also has a mounting hole 34 (Figure 5) on the side opposite to the side with the hook mechanism 32 in its longitudinal direction.

[0015] When attaching the regenerative resistor 14 to the flange 16, first, as shown in Figure 5, move the regenerative resistor 14 relative to the flange 16 in the direction indicated by arrow 30 so that the hook mechanism 32 engages with the opening 28. Next, align the mounting hole 34 of the regenerative resistor 14 with the fixing hole 22 of the stepped portion 20 of the flange 16, and fix the regenerative resistor 14 to the flange 16 using fasteners such as screws (not shown).

[0016] Figure 7 shows the state in which the regenerative resistor 14 is fixed to the flange 16 by the above-described operation. In the first embodiment, the parts of the flange 16 that the regenerative resistor 14 substantially contacts are limited to the part 38 in which the hook mechanism 32 is engaged, the part 40 corresponding to the stepped part 20, and the top part 26 of the projection 24 described above. Therefore, the contact area between the regenerative resistor 14 and the flange 16 is significantly smaller compared to the case in which almost the entire surface of the regenerative resistor 14 is in contact with the flange 16. In addition, by using the hook mechanism, the number of parts such as screws can be reduced.

[0017] In the first embodiment, the hook mechanism 32 has two hooks 32a and 32b of different shapes, but it is not limited to this. For example, the hook mechanism may have one hook, or it may have two or more hooks of the same shape and dimensions.

[0018] (Second example) Figure 8 shows the flange 16a of the motor drive device according to the second embodiment. The flange 16a has a stepped portion 20a in which fixing holes 22a are formed, and also has a stepped portion 20b in which fixing holes 22b are formed on the side opposite to the side with the stepped portion 20a in the longitudinal direction. In other words, the second embodiment generally corresponds to having multiple stepped portions (two in the illustrated example) instead of the one that was present in the first embodiment.

[0019] The regenerative resistor in the second embodiment does not have a hook mechanism like the regenerative resistor 14 in the first embodiment, but instead has two mounting holes like the hole 34 shown in Figure 5. These mounting holes are aligned and fixed to the holes 22a and 22b in the stepped portions 20a and 20b using fasteners such as screws (not shown).

[0020] In the second embodiment, the portion of the flange 16 that substantially contacts the regenerative resistor 14 is limited to two portions corresponding to the stepped portions 20a and 20b. Therefore, the contact area between the regenerative resistor 14 and the flange 16 is significantly smaller compared to the case where almost the entire surface of the regenerative resistor 14 contacts the flange 16.

[0021] (Third embodiment) Figure 9 shows a regenerative resistor 14a of a motor drive device according to the third embodiment, and Figure 10 is a partially enlarged view of Figure 9. The regenerative resistor 14a has a hook mechanism 32, similar to the regenerative resistor 14 in the first embodiment, but does not have a mounting hole on the opposite side in the longitudinal direction, and instead has an elastically deformable second hook mechanism 42. In the illustrated example, the second hook mechanism is a tab-shaped member configured to be elastically deformable.

[0022] Figure 11 shows an example of the installation operation of the regenerative resistor 14a to the flange 16. First, the regenerative resistor 14a is moved relative to the flange 16 in the direction indicated by arrow 30 so that the hook mechanism 32 engages with the opening 28. Next, the tab-shaped member 42 is bent inward in the direction indicated by arrow 44 and pushed into the flange 16, thereby fixing the regenerative resistor 14a to the flange 16. In the third embodiment as well, it is preferable that the flange 16 has the same projection 24 as in the first embodiment.

[0023] Figure 12 shows the state in which the regenerative resistor 14a is fixed to the flange 16 by the operation described above. In the third embodiment, the portion of the flange 16 that substantially contacts the regenerative resistor 14a is limited to the portion 38 in which the hook mechanism 32 is engaged, the portion 46 in which the tab-shaped member 42 is engaged, and the top portion 26 of the projection 24 (Figure 3). Therefore, the contact area between the regenerative resistor 14a and the flange 16 is significantly smaller compared to the case in which almost the entire surface of the regenerative resistor 14a is in contact with the flange 16. In addition, by using two hook mechanisms, there is no need to use fixing parts such as screws.

[0024] (Fourth embodiment) Figure 13 shows the regenerative resistor 14b of the motor drive device according to the fourth embodiment, and Figure 14 is a partially enlarged view of Figure 13. The regenerative resistor 14b has an elastically deformable second hook mechanism (tab-shaped member) 42, similar to the regenerative resistor 14a in the third embodiment, but does not have a hook mechanism on the opposite side in the longitudinal direction, and instead has an elastically deformable third hook mechanism 48. In the illustrated example, the third hook mechanism 48 has a U-shaped portion 48a that is substantially U-shaped in side view, and a tab-shaped portion 48b that extends longitudinally outward from the U-shaped portion 48a, and can be formed, for example, by bending sheet metal.

[0025] Figure 15 is a schematic plan view of the flange 16b of the motor drive device according to the fourth embodiment. In the fourth embodiment, as will be described later, the regenerative resistor 14b is fixed to the flange 16b by only two hook mechanisms, so there is no need to form steps or protrusions on the surface 18b of the flange 16b facing the regenerative resistor 14b.

[0026] Figure 16 is a magnified view of a portion of the flange 16b, and Figure 17 shows an example of the operation of attaching the regenerative resistor 14b to the flange 16b. First, the regenerative resistor 14b is moved toward the flange 16b in a direction approximately perpendicular to the surface 18b, as indicated by arrow 50. Next, the regenerative resistor 14b is moved relative to the flange 16b so that the tab-shaped portion 48b of the hook mechanism 48 is inserted into the slit 49 of the flange 16b. At this time, if the U-shaped portion 48a of the hook mechanism 48 is housed in the opening or recess 28b of the flange 16b, accurate positioning of the regenerative resistor 14b becomes possible. Next, the regenerative resistor 14a can be fixed to the flange 16 by bending the hook 42 and pushing it into the flange 16b.

[0027] Figure 18 shows the state in which the regenerative resistor 14b is fixed to the flange 16b by the operation described above. In the fourth embodiment, the portion of the flange 16b that the regenerative resistor 14b substantially contacts is limited to the portion 46 in which the second hook mechanism 42 is engaged and the portion 52 in which the third hook mechanism 48 is engaged. Therefore, the contact area between the regenerative resistor 14b and the flange 16b is very small, and the amount of heat conducted from the regenerative resistor 14b to the flange 16b is also very small.

[0028] Figure 19 is a side view of the configuration shown in Figure 18, and Figure 20 is a partially enlarged view of the area indicated by reference numeral 54 in Figure 19. As described above, in the fourth embodiment, there is no need to provide steps or protrusions on the flange 16b to reduce the contact area with the regenerative resistor 14b, so a gap with a certain width G can be formed between the bottom surface of the regenerative resistor 14b and the surface 18b of the flange 16b. The size of the width G can be set to any value based on the shape and dimensions of the regenerative resistor 14b and the flange 16b, but if G is too large the motor drive device will be large, and if G is too small the heat from the regenerative resistor will be easily transferred to the flange, so it is preferable to set an appropriate value that takes these factors into consideration.

[0029] (Fifth example) Figure 21 is a plan view showing the flange 16c and regenerative resistor 14 according to the fifth embodiment, Figure 22 is a cross-sectional view along the line XXII-XXII in Figure 21, and Figure 23 is a partially enlarged view of region 60 in Figure 22. In the fifth embodiment, the upper surface 62 of the regenerative resistor 14 is more convex than the upper surface 64 of the flange 16c. For convenience in this embodiment, the surface of the regenerative resistor 14 facing the surface 18 of the flange 16c is considered the lower surface, and the opposite surface 62 is considered the upper surface. The same applies to the flange 16c.

[0030] More specifically, by providing at least one projection 24c larger than the projection 24 in the first embodiment on the surface 18 of the flange 16c facing the regenerative resistor 14, the upper surface 62 of the regenerative resistor 14 protrudes upward above the upper surface 64 of the flange 16c. This allows the upper surface 62 of the regenerative resistor 14 to come into contact with the mounting object of the motor drive device (for example, the control panel 66 of a machine tool as schematically shown), and the heat from the regenerative resistor 14 can be actively dissipated to the control panel 66.

[0031] Figure 24 is a side cross-sectional view similar to Figure 22, showing the flange 160 and regenerative resistor 140 according to the comparative example, and Figure 25 is a partially enlarged view of region 168 in Figure 24. In this comparative example, the surface 118 of the flange 160 facing the regenerative resistor 140 does not have any protrusions, so the regenerative resistor 140 and the flange 160 are in contact with each other over a considerably large area, and the upper surface 162 of the regenerative resistor 140 is recessed below the upper surface 164 of the flange 160. Therefore, in the comparative example, the upper surface 162 of the regenerative resistor 140 is covered with a thermal conductive sheet or the like to fill the gap between the regenerative resistor 140 and the control panel, which led to an increase in the number of parts and a higher cost for the motor drive device.

[0032] However, in the fifth embodiment, since the upper surface 62 of the regenerative resistor 14 is more convex outward than the upper surface 64 of the flange 16c, a heat conductive sheet is not required, and the number of parts can be reduced.

[0033] The above embodiments can be combined as appropriate. For example, the feature in the fifth embodiment, in which the upper surface of the regenerative resistor is more convex outward than the upper surface of the flange, can be applied to any of the first to fourth embodiments.

[0034] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0035] The following additional information is disclosed regarding the above embodiments and modifications.

[0036] (Note 1) A motor drive device comprising a drive circuit component for driving a motor, a regenerative resistor for consuming regenerative power from the motor, and a flange to which the drive circuit component and the regenerative resistor are attached, wherein the surface of the flange facing the regenerative resistor has at least one stepped portion formed of the same material as the flange that contacts the regenerative resistor.

[0037] (Note 2) The motor drive device according to Appendix 1, wherein a fixing hole for fixing the regenerative resistor is formed in the stepped portion.

[0038] (Note 3) A motor drive device comprising a drive circuit component for driving a motor, a regenerative resistor for consuming regenerative power from the motor, and a flange to which the drive circuit component and the regenerative resistor are attached, wherein the opposing surfaces of the regenerative resistor and the flange do not come into contact with each other.

[0039] (Note 4) The motor drive device according to any one of appendices 1 to 3, wherein the regenerative resistor has at least one hook mechanism that engages with the flange.

[0040] (Note 5) The motor drive device according to any one of the appendices 1 to 4, wherein the upper surface of the regenerative resistor is more convex than the upper surface of the flange. [Explanation of symbols]

[0041] 2 motors 10 Motor drive unit 12 Power elements 14th generation resistance 16 flange 14th generation resistance 20 Step section 22 Fixing hole 32, 42, 48 Hook mechanism 34 mounting holes 49 Slits 62, 64 Top 66 Control Panel

Claims

1. A drive circuit component for driving the motor; a regenerative resistor for consuming regenerative power from the motor; a flange to which the drive circuit components and the regenerative resistor are attached; A motor drive device having A motor drive device, wherein a surface of the flange facing the regenerative resistor has at least one step portion that contacts the regenerative resistor and is formed from the same material as the flange.

2. The motor drive device according to claim 1 , wherein the step portion is formed with a fixing hole for fixing the regenerative resistor.

3. A drive circuit component for driving the motor; a regenerative resistor for consuming regenerative power from the motor; a flange to which the drive circuit components and the regenerative resistor are attached; A motor drive device having A motor drive device, wherein the opposing surfaces of the regenerative resistor and the flange do not come into contact with each other.

4. 4. The motor drive device according to claim 1, wherein the regenerative resistor has at least one hook mechanism that engages with the flange.

5. 4. The motor drive device according to claim 1, wherein an upper surface of the regenerative resistor is more convex than an upper surface of the flange.

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