Driving device and driving method

Abstract

To provide a technique that can add up the driving forces of a plurality of driving means while preventing the drives of the driving means from loading on each other.SOLUTION: A driving device comprises: an output shaft 60; a first member 30 and a second member 40 configured to be rotatable relative to the output shaft 60; a third member 50 fastened to the output shaft 60; a vibration type actuator 10 that drives to rotate one member of the first member 30 and the second member 40 around the output shaft 60; an electromagnetic motor 20 that drives to rotate the other member of the first member 30 and the second member 40 around the output shaft 60; and rolling elements 80 that are rotatably held by the second member 40 and are in contact with and sandwiched by the first member 30 and the third member 50. At least one of the vibration type actuator 10 and the electromagnetic motor 20 drives to rotate the third member 50 and the output shaft 60 in an integrated manner.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drive device and a drive method. [Background technology]

[0002] A vibration actuator that can be included in the driving device has a vibrating body that is in pressure contact with a moving body to be driven. This vibration actuator is used as a vibration wave motor that moves the moving body relatively by utilizing friction generated by the driving force of vibration excited in the vibrating body. In addition, a rotary vibration actuator, which is one type of vibration actuator, is used, for example, to move the lens for the autofocus function or zoom function of a camera, or as a driving source for the pan-tilt operation of a camera.

[0003] Since the vibration actuator has a structure that transmits a driving force to the moving body by using friction, it is effective to increase the pressure related to the pressure contact between the vibration body and the moving body in order to increase the torque (generated force). However, if the above-mentioned pressure is increased too much, the loss due to friction increases, and there is a risk that the temperature of the vibration body or the moving body will rise significantly during driving, or the durability will decrease due to wear of the frictional parts, so it is difficult to increase the pressure beyond an appropriate range. As one of the countermeasures, a method is conceivable in which a plurality of vibration actuators are simultaneously used as a plurality of driving means, the driving forces of each vibration actuator are transmitted to one output shaft, and the driving forces are synthesized (combined) to increase the torque. For example, Patent Document 1 describes a technology in which a plurality of vibration actuators are connected to one output shaft, and the driving forces of each vibration actuator are superimposed to increase the torque (generated force). Specifically, Patent Document 1 controls the driving frequency and driving voltage so that the output characteristics such as the rotation speed of each vibration actuator are matched. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-205190 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology described in Patent Document 1, when differences in output characteristics arise due to individual differences in the vibration actuators, the driving forces of the vibration actuators cannot be added together, and multiple vibration actuators end up acting as a load on each other, which is an issue.

[0006] The present invention has been made in consideration of such problems, and aims to provide a technology that can add up the driving forces of multiple driving means without the driving of each driving means becoming a load on each other. [Means for solving the problem]

[0007] The driving device of the present invention comprises an output shaft, a first member and a second member configured to be rotatable relative to the output shaft, a third member fixed to the output shaft, a vibration actuator that rotates one of the first member and the second member around the output shaft, an electromagnetic motor that rotates the other member different from the one of the first member and the second member around the output shaft, and a rolling element that is rotatably held by the second member and is clamped in contact with the first member and the third member, and the third member and the output shaft rotate together when at least one of the vibration actuator and the electromagnetic motor is driven. The present invention also includes a method for driving the above-mentioned drive device. Effect of the Invention

[0008] According to the present invention, the driving forces of a plurality of driving means (vibration actuators and electromagnetic motors) can be added together without the driving of each of the driving means acting as a load on each other. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a first example of a schematic configuration of a drive device according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing a first example of a schematic configuration of a drive device according to a first embodiment. [Diagram 3] 1 is an exploded perspective view showing an example of a schematic configuration of a vibration actuator according to a first embodiment. [Figure 4] 3A and 3B are diagrams illustrating two bending vibration modes (mode A and mode B) of the vibrator according to the first embodiment. [Diagram 5] 3 is a diagram showing an example of rotation characteristics of a first member that is rotationally driven by a vibration actuator and a second member that is rotationally driven by an electromagnetic motor in the drive device according to the first embodiment. FIG. [Figure 6] 5 is a diagram showing an example of the relationship between the rotation speed of a second member and the rotation speed and torque of a third member in the drive device according to the first embodiment. FIG. [Figure 7] 5A to 5C are diagrams illustrating an example of a movement pattern of a first member, a second member, and a third member in the drive device according to the first embodiment. [Figure 8] FIG. 4 is a perspective view showing a second example of the schematic configuration of the drive device according to the first embodiment. [Figure 9] 4 is a cross-sectional view showing a third example of the schematic configuration of the drive device according to the first embodiment. FIG. [Figure 10] FIG. 11 is a perspective view showing an example of a schematic configuration of a drive device according to a second embodiment. [Figure 11] FIG. 13 shows a third embodiment, and is a diagram showing an example of a schematic configuration of a camera head device including a plurality of driving devices described in the first and second embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (First embodiment) First, the first embodiment will be described.

[0012] FIG. 1 is a perspective view showing a first example of a schematic configuration of a drive device 100 according to the first embodiment. The drive device 100 according to the first example of the first embodiment shown in FIG. 1 is described as a "drive device 100-11". Specifically, FIG. 1(a) is a perspective view of the internal configuration of the drive device 100-11, and FIG. 1(b) is a perspective view of the internal configuration of the drive device 100-11 disassembled. In FIG. 1(a) and FIG. 1(b), the same configuration is given the same reference numeral. Also, FIG. 1(a) and FIG. 1(b) show a rotation coordinate system in which the axial direction of the output shaft 60 is the z direction, the radial direction is the r direction, and the counterclockwise direction as viewed from the Z direction is positive θ.

[0013] As shown in Figures 1(a) and 1(b), the driving device 100-11 includes a vibration actuator 10, an electromagnetic motor 20, a first member 30, a second member 40, a third member 50, an output shaft 60, a pinion gear 70, and a rolling element 80.

[0014] 1(a), the vibration actuator 10 is in pressure contact with the first member 30. Therefore, the driving force generated by exciting the vibration actuator 10 is transmitted to the first member 30, causing the first member 30 to rotate around the output shaft 60 relative to the vibration actuator 10. That is, in the driving device 100-11, the vibration actuator 10 drives the first member 30 to rotate around the output shaft 60. Since the first member 30 is frictionally driven by this vibration actuator 10, positional deviation (backlash) is small, and it is possible to precisely position and drive the first member 30.

[0015] Further, the driving force of the electromagnetic motor 20 is transmitted to the spur gear 41 provided on the outer periphery of the second member 40 via the pinion gear 70, and the second member 40 rotates around the output shaft 60. That is, in the drive device 100-11, the electromagnetic motor 20 drives the second member 40 to rotate around the output shaft 60. At this time, the pinion gear 70 and the spur gear 41 are provided with an appropriate backlash. Note that, since Fig. 1(a) and Fig. 1(b) are schematic diagrams, the pitches of the teeth of the pinion gear 70 and the teeth of the spur gear 41 do not match, but in reality, the pitches match. Also, Fig. 1(a) and Fig. 1(b) show an example in which the number of teeth of the pinion gear 70 is smaller than the number of teeth of the spur gear 41, i.e., the gear ratio is set to reduce the speed and increase the torque, but this embodiment is not limited to this. For example, a configuration in which the pinion gear 70 and the spur gear 41 have the same number of teeth, or a configuration in which the pinion gear 70 has a greater number of teeth than the spur gear 41, can also be applied to this embodiment.

[0016] FIG. 1(b) is a perspective view of the driving device 100-11 shown in FIG. 1(a) exploded in the direction of the rotation axis of the output shaft 60. Specifically, FIG. 1(b) is a view for explaining a method of positioning the rolling elements 80, which are, for example, stainless steel balls, at a predetermined position relative to the second member 40. FIG. 1(b) illustrates a state in which a plurality of rolling elements 80 are inserted into a plurality of holes 42 arranged in a line on a circumference of the second member 40. In the actual driving device 100-11, the plurality of rolling elements 80 are supported so as to be in contact with and sandwiched between the first member 30 and the third member 50 and to be in pressurized contact with each other while being inserted into the plurality of holes 42 of the second member 40. Since the rolling elements 80 are inserted into the holes 42 of the second member 40 by this structure, the rolling elements 80 can move relatively while rolling with respect to the first member 30 and the third member 50 while maintaining a predetermined positional relationship with respect to the second member 40.

[0017] Fig. 2 is a cross-sectional view showing a first example of a schematic configuration of the drive device 100 according to the first embodiment. Specifically, Fig. 2 is a cross-sectional view of a drive device 100-11 according to the first example of the first embodiment, cut along a plane passing through the rotation axis L of the output shaft 60. In Fig. 2, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0018] 2, the driving device 100-11 includes an exterior part 90 and bearings 91 to 94 in addition to the components (10 to 80) shown in Fig. 1(a) and Fig. 1(b). In the driving device 100-11, the first member 30, the second member 40, and the third member 50 are each inserted into an output shaft 60, as shown in Fig. 2.

[0019] The first member 30 is supported by the output shaft 60 via a bearing 92. Therefore, the first member 30 is configured to be rotatable relative to the output shaft 60 around the rotation axis L. The second member 40 is supported by the output shaft 60 via a bearing 93. Therefore, the second member 40 is configured to be rotatable relative to the output shaft 60 around the rotation axis L. The third member 50 is fixedly attached to the output shaft 60. Furthermore, the output shaft 60 is supported by the exterior part 90 via two bearings 91 and 94. With the above configuration, the first member 30, the second member 40, the third member 50, and the output shaft 60 are rotatable around the rotation axis L.

[0020] The vibration actuator 10 is supported so as not to move relative to the exterior part 90 in the circumferential direction. The vibration actuator 10 is in pressurized contact with the first member 30 using a pressurizing means (not shown). As the pressurizing means in this case, for example, a spring pressurizing means such as a coil spring or a leaf spring, or a magnetic pressurizing means using a magnetic force can be used.

[0021] The rolling element 80 is supported rotatably relative to the second member 40, and is sandwiched between the first member 30 and the third member 50 in a pressurized state by a pressurizing means (not shown). As the pressurizing means for pressurizing the first member 30 and the third member 50 to the rolling element 80, a plate spring, a wave washer, or the like can be used in addition to a coil spring. Note that the pressurizing means for pressurizing the first member 30 and the third member 50 to the rolling element 80 may also be the pressurizing means of the vibration actuator 10.

[0022] Since the rolling body 80 is in pressurized contact with the first member 30 and the third member 50, the rolling body 80 will not slip relative to the first member 30 or the third member 50 unless the frictional force acting between the rolling body 80 and the first member 30 or the frictional force acting between the rolling body 80 and the third member 50 is exceeded. In addition, the rolling body 80 can move (revolve) while rolling on the contact surface with the first member 30 and the third member 50. At this time, the rolling body 80 needs to rotate on its own axis while in sliding contact with the second member 40, so in order to make this possible, a minute gap is provided between the second member 40 (more specifically, the hole 42 of the second member 40) and the rolling body 80.

[0023] Although the rolling element 80 shown in FIG. 1(b) and FIG. 2 is an example of using a stainless steel ball, the present embodiment is not limited to this stainless steel ball. For example, the present embodiment is also applicable to a form in which a cermet ball, a ceramic ball, a resin ball, or the like is used as the rolling element 80. The shape of the rolling element 80 is not limited to the shape of a ball shown in FIG. 1(b) and FIG. 2, and the present embodiment is also applicable to a form in which a member having a columnar or cylindrical shape called a roller is used. In this case, the second member 40 is provided with a hole 42 corresponding to the shape of the rolling element 80, and the rolling element 80 is fitted into the hole 42, thereby obtaining the same effect.

[0024] Furthermore, in this embodiment, the rolling body 80 may be configured to include a gear. Specifically, for example, a gear is formed on a cylindrical or conical member as the rolling body 80. In this case, a gear meshing with the gear of the rolling body 80 can be formed at the portion of the first member 30 and the third member 50 that contacts the gear of the rolling body 80, thereby transmitting the driving force. Here, when a gear is used for the rolling body 80, this gear does not have a sliding contact with the second member 40, but is supported by the second member 40 and needs to be configured to be rotatable around an axis along the radial direction of the second member 40. In addition, in order to realize a drive mechanism capable of highly accurate positioning, it is preferable to apply a preload by sandwiching the gear of the rolling body 80 between the first member 30 and the third member 50, thereby reducing backlash.

[0025] 3 is an exploded perspective view showing an example of a schematic configuration of the vibration actuator 10 according to the first embodiment. As shown in FIG. 1, the vibration actuator 10 includes a vibrating body 13, a buffer member 14, a pressure transmitting member 15, and a vibrating body support part 16.

[0026] 3, the vibrating body 13 includes an elastic body 11 having two protrusions 11a and 11b, and a piezoelectric body 12. More specifically, the vibrating body 13 is configured such that the elastic body 11 and the piezoelectric body 12 are bonded together and supported by a vibrating body support section 16 via a buffer member 14 and a pressure transmission member 15. In this embodiment, the piezoelectric body 12 is an electro-mechanical energy conversion element.

[0027] The elastic body 11 of the vibrating body 13 is preferably made of a material with low vibration attenuation, for example, a metal such as stainless steel or ceramic. Regarding the manufacture of the elastic body 11, the two protrusions 11a and 11b may be integrally provided by press molding or cutting, or the two protrusions 11a and 11b may be manufactured separately and then fixed to the elastic body 11 by welding, adhesive, or the like.

[0028] The piezoelectric body 12 of the vibrating body 13 uses, for example, lead zirconate titanate. The piezoelectric body 12 may also be made mainly of a lead-free piezoelectric material such as barium titanate. Here, "lead-free" means that the lead content is 1000 ppm or less.

[0029] Furthermore, the vibrating body 13 (more specifically, the protrusions 11a and 11b of the elastic body 11) is in pressure contact with the first member 30 via a spring (not shown) through the pressure transmission member 15 and the buffer member 14. Here, the buffer member 14 is made of felt or the like. Moreover, the pressure transmission member 15 is configured so as not to impede the vibration of the vibrating body 13.

[0030] Fig. 4 is a diagram showing two bending vibration modes (mode A and mode B) of the vibrator 13 according to the first embodiment. In Fig. 4, the same components as those shown in Fig. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0031] 4(a) and 4(b) show an elastic body 11 having two protrusions 11a and 11b, and a vibrating body 13 having a piezoelectric body 12. In FIG.

[0032] The bending vibration mode in Fig. 4(a) shows the case of A-mode. A-mode is a secondary bending motion in the long side direction (X-direction in Fig. 4(a)) of rectangular vibrating body 13, and has three nodal lines parallel to the short side direction (Y-direction in Fig. 4(a)). Here, protrusions 11a and 11b are disposed near positions that become nodes in A-mode vibration, and perform reciprocating motion in the X-direction in Fig. 4(a) due to A-mode vibration.

[0033] The bending vibration mode in Fig. 4(b) shows the case of B mode. B mode is a primary bending vibration in the short side direction (Y direction in Fig. 4(a)) of the rectangular vibrating body 13, and has two nodal lines parallel to the long side direction (X direction in Fig. 4(a)). Here, the nodal lines in A mode shown in Fig. 4(a) and the nodal lines in B mode shown in Fig. 4(b) are formed so as to be approximately perpendicular in the XY plane. In addition, the protrusions 11a and 11b are disposed near positions that become antinodes in the B mode vibration, and perform reciprocating motion in the Z direction in Fig. 4(b) by the B mode vibration.

[0034] By generating vibrations in A mode shown in Fig. 4(a) and B mode shown in Fig. 4(b) with a predetermined phase difference, elliptical motion is generated at the tips of the protrusions 11a and 11b, and a driving force in the X direction in Fig. 4(a) can be applied. Note that a flexible printed circuit board (not shown) is attached to the piezoelectric body 12, and by applying an AC voltage to the piezoelectric body 12 from this flexible printed circuit board (not shown), the two bending vibration modes shown in Fig. 4 can be generated.

[0035] Next, the operation of the driving device 100-11 according to the first example of the first embodiment will be described. First, a case will be described in which the third member 50 and the output shaft 60 are rotated integrally by driving either the vibration actuator 10 or the electromagnetic motor 20.

[0036] First, a case where only the vibration actuator 10 is driven will be described. In this case, when only the first member 30 rotates by receiving the thrust of the vibration actuator 10 and the second member 40 is fixed, the rolling element 80 rotates on its axis due to a frictional force in the circumferential direction about the rotation axis L between the rolling element 80 and the first member 30. Furthermore, the third member 50 rotates on its axis due to a frictional force in the circumferential direction about the rotation axis L between the rotating rolling element 80 and the third member 50, and the third member 50 and the output shaft 60 rotate integrally.

[0037] Next, a case where only the electromagnetic motor 20 is driven will be described. In this case, when only the second member 40 rotates due to the driving force of the electromagnetic motor 20 and the first member 30 is fixed, the rolling element 80 receives a circumferential force around the rotation axis L from the hole 42 of the second member 40 due to the rotation of the second member 40, and the rolling element 80 revolves around the rotation axis L. When the rolling element 80 revolves, the rolling element 80 receives a circumferential friction force around the rotation axis L from the contact surface between the first member 30 and the third member 50, so the rolling element 80 rolls and rotates. Since the first member 30 is supported so as not to rotate by the holding force due to the contact with the vibration actuator 10, the driving force of the electromagnetic motor 20 is transmitted as a force to rotate the third member 50 via the second member 40 and the rolling element 80. Then, the third member 50 and the output shaft 60 rotate integrally.

[0038] As described above, in the driving device 100-11, the third member 50 and the output shaft 60 can be rotationally driven together by driving either one of the vibration actuator 10 and the electromagnetic motor 20. As a result, even if, for example, one of the vibration actuator 10 and the electromagnetic motor 20 stops and cannot be driven, the other one can be driven independently to drive the driving device 100-11.

[0039] Next, a case will be described in which the vibration actuator 10 and the electromagnetic motor 20 are both (simultaneously) driven to rotate the third member 50 and the output shaft 60 together with a large combined driving force of the vibration actuator 10 and the electromagnetic motor 20.

[0040] By simultaneously driving the vibration actuator 10 and the electromagnetic motor 20, the driving forces of the vibration actuator 10 and the electromagnetic motor 20 are combined (added) and transmitted to the third member 50. As a result, the combined driving force is output as the output of the driving device 100-11 from the output shaft 60 which rotates integrally with the third member 50. The rotation speed and torque of the output shaft 60 at this time will be described below.

[0041] The rotation speeds and torques of the first member 30 driven by the vibration actuator 10, the second member 40 driven by the electromagnetic motor 20, and the third member 50 rotating integrally with the output shaft 60 are defined as follows. First member 30: rotation speed N1, torque T1 Second member 40: rotation speed N2, torque T2 Third member 50: rotation speed N3, torque T3 The unit of the rotation speed is rpm, and the unit of the torque is Nm. The rotation speeds N1, N2, and N3 and the torques T1, T2, and T3 are positive in the counterclockwise direction as viewed from the top of the paper of FIG. 1, that is, the θ direction in the rotation coordinate system shown in FIG. 1. Specifically, the rotation speed of the first member 30 is N1, and the torque of the first member 30 is T1 when the first member 30 rotates counterclockwise with respect to the rotation axis L of the output shaft 60. Similarly, the rotation speed of the second member 40 is N2, and the torque of the second member 40 is T2 when the second member 40 rotates counterclockwise with respect to the rotation axis L of the output shaft 60. Similarly, the rotation speed of the third member 50 is N3, and the torque of the third member 50 is T3 when the third member 50 rotates counterclockwise with respect to the rotation axis L of the output shaft 60.

[0042] First, the rotation speed will be described. Here, it is assumed that no slippage occurs between the rolling body 80 and the first member 30 and the third member 50. At this time, the rolling body 80 revolves around the rotation axis L while being sandwiched between the first member 30 and the third member 50, so the number of revolutions of the rolling body 80 is the average of the number of revolutions N1 of the first member 30 and the number of revolutions N3 of the third member 50. In addition, the number of revolutions of the rolling body 80 is equal to the number of revolutions of the second member 40 that holds the rolling body 80. In other words, the number of revolutions N2 of the second member 40 is the average of the number of revolutions N1 of the first member 30 and the number of revolutions N3 of the third member 50. The relationship is expressed by the following formula (1).

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[0043] From formula (1), the rotation speed N3 of the third member 50 is expressed by the following formula (2). N3 = 2 N2 - N1 (2)

[0044] From formula (2), it can be seen that the rotation speed N3 of the third member 50 changes its rotation direction depending on the relationship between the rotation speed N2 of the second member 40 and the rotation speed N1 of the first member 30.

number

[0045] Next, torque will be described. The kinetic energy (W) during rotation of the first member 30, the second member 40, and the third member 50 is expressed by the following equations (3) to (5), respectively, in terms of the relationship between torque and rotation speed. Kinetic energy of the first member 30: W1=2π T1 N1 / 60 (3) Kinetic energy of the second member 40: W2=2π T2 N2 / 60 (4) Kinetic energy of the third member 50: W3 = 2π T3 N3 / 60 (5)

[0046] The kinetic energy W3 of the third member 50 is equal to the kinetic energy of the output shaft 60. When the energy loss due to the rolling elements 80, the bearings 91-94, etc. is extremely small and can be ignored, the kinetic energy W3 of the third member 50 is the sum of the kinetic energy W1 of the first member 30 and the kinetic energy W2 of the second member 40, and is given by the following formula (6). W3 = W1 + W2 (6)

[0047] And from the above-mentioned formulas (3) to (6), the following formula (7) is obtained. T3·N3=T1·N1+T2·N2 ···(7)

[0048] From equations (2) and (7), the torque T3 of the third member 50 is given by the following equation (8).

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[0049] Next, the output of the third member 50 when the vibration actuator 10 is driven and the electromagnetic motor 20 is stopped will be described using the above formula. Since the electromagnetic motor 20 is stopped, the rotation speed N2 of the second member 40 = 0 rpm. In this case, from formula (2), the rotation speed N3 of the third member 50 = -N1, and the absolute values ​​of the rotation speed N1 of the first member 30 and the rotation speed N3 of the third member 50 are equal, but their directions are opposite. In this case, from formula (8), the torque T3 of the third member 50 = -T1, and the absolute value of the torque T3 of the third member 50 is equal to the torque T1 of the first member 30, but their directions are opposite.

[0050] Next, the output of the third member 50 when the electromagnetic motor 20 is driven and the vibration actuator 10 is stopped will be described using the above-mentioned formula. Since the vibration actuator 10 is stopped, the rotation speed N1 of the first member 30 = 0 rpm. In this case, from formula (2), the rotation speed N3 of the third member 50 = 2·N2, and the rotation speed N3 of the third member 50 is twice the absolute value of the rotation speed N2 of the second member 40, and the direction is the same.

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[0051] Next, a method for simultaneously driving the vibration actuator 10 and the electromagnetic motor 20 to obtain a large output from the output shaft 60 will be described.

[0052] FIG. 5 is a diagram showing an example of the rotation characteristics of the first member 30 rotated by the vibration actuator 10 and the second member 40 rotated by the electromagnetic motor 20 in the driving device 100 according to the first embodiment. In FIG. 5, the horizontal axis indicates the rotation speed, and the vertical axis indicates the torque. Since the rotation speed N1 and torque T1 of the first member 30 are constant, only one black circle (N1=100 rpm, T1=0.5 Nm) is plotted in FIG. 5. In addition, in FIG. 5, two dashed lines are used to explain the case where the rotation speed N2 and torque T2 of the second member 40 are variable. Note that the rotation speed N2 and torque T2 of the second member 40 are on the dashed lines in FIG. 5 when they satisfy the maximum output, and when they are in the first quadrant, the rotation speed N2 and torque T2 of the second member 40 can be in the area below the dashed lines. Conversely, when in the third quadrant, the rotation speed N2 and torque T2 of the second member 40 can be in the region above the dashed line. Since the rotation speed N2 and torque T2 change sign depending on the rotation direction of the second member 40, the straight line of the torque T2 of the second member 40 becomes discontinuous at the rotation speed of 0 rpm.

[0053] FIG. 6 is a diagram showing an example of the relationship between the rotation speed N2 of the second member 40 and the rotation speed N3 and torque T3 of the third member 50 in the drive device 100 according to the first embodiment. Specifically, FIG. 6(a) is a characteristic diagram showing the change in the rotation speed N3 and torque T3 of the third member 50 (output shaft 60) relative to the rotation speed N2 when the rotation speed N2 of the second member 40 is in a positive range. Also, FIG. 6(b) is a characteristic diagram showing the change in the rotation speed N3 and torque T3 of the third member 50 (output shaft 60) relative to the rotation speed N2 when the rotation speed N2 of the second member 40 is in a negative range. In FIG. 6(a) and FIG. 6(b), the solid line indicates the rotation speed N3 of the third member 50 (output shaft 60), and the dashed line indicates the torque T3 of the third member 50 (output shaft 60). In addition, the values ​​shown on the vertical and horizontal axes in FIG. 5, FIG. 6(a) and FIG. 6(b) are shown as examples of characteristics, and the values ​​do not necessarily have to be those shown.

[0054] Next, a description will be given of a driving method for rotating the third member 50 (output shaft 60) at the rotation speed N3 in the same direction as the rotation speed N1 of the first member 30. In other words, since N3 / N1>0, the following formula (9) is obtained from the above formula (2). N3 / N1=2 N2 / N1-1>0 N2 / N1>0.5 (9) When this formula (9) is satisfied, the third member 50 (the output shaft 60) can be driven in the same direction as the first member 30.

[0055] Furthermore, when N2 / N1=0.5, that is, when N2=N1 / 2, the rotation speed N3 of the third member 50 (output shaft 60) becomes 0 rpm. Furthermore, when N2 / N1<0.5, the third member 50 (output shaft 60) can be rotated in the opposite direction to the first member 30.

[0056] Next, a description will be given of a driving method (including the same rotation speed) for increasing the rotation speed N3 of the third member 50 (output shaft 60) to be higher than the rotation speed N1 of the first member 30. That is, since N3 is equal to or higher than N1, the following formula (10) is obtained from the above formula (2). N3=2·N2-N1≧N1 N2 ≧ N1 (10) When formula (10) is satisfied, the rotation speed N3 of the third member 50 (output shaft 60) can be made higher than the rotation speed N1 of the first member 30.

[0057] Next, a description will be given of a driving method (including the same torque) for making the torque T3 of the third member 50 (output shaft 60) greater than the torque T1 of the first member 30. In other words, since T3≧T1, the following formula (11) is obtained from the above formula (8).

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[0058] Next, a driving method in which the third member 50 (output shaft 60) decelerates and increases the torque with respect to the first member 30 will be described. In FIG. 6(a), when the rotation speed N2 of the second member 40 is in a positive range (counterclockwise), the rotation speed N3 of the third member 50 is proportional to the rotation speed N2 of the second member 40, and the rotation direction of the rotation speed N2 is reversed when the rotation speed N2 reaches a predetermined value (50 rpm). In addition, in FIG. 6(a), when the rotation speed N2 of the second member 40 is 50 rpm at which the rotation speed N3 of the third member 50 is 0 rpm, the torque T3 of the third member 50 becomes infinite. However, in reality, when the torque exceeds a certain value, slippage occurs between the rolling element 80 and the first member 30 or the third member 50, so the driving device 100-11 cannot output a torque above a certain value.

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[0059] 6(b), when the rotation speed N2 of the second member 40 is in the negative range (clockwise), the rotation speed N3 of the third member 50 is proportional to the rotation speed N2 of the second member 40. When the rotation speed N2 of the second member 40 increases in the negative direction (clockwise), the rotation speed N3 of the third member 50 also increases in the negative direction (clockwise), and the torque T3 of the third member 50 decreases accordingly.

[0060] By utilizing these characteristics, when the rotation speed N1 and torque T1 of the first member 30 are kept constant, the rotation speed N2 and torque T2 of the second member 40 must be selected according to the output required of the third member 50 (output shaft 60).

[0061] Fig. 7 is a diagram showing an example of an operation pattern of the first member 30, the second member 40, and the third member 50 in the drive device 100 according to the first embodiment. Specifically, Fig. 7 shows a combination pattern of the rotation speed N1 and torque T1 of the first member 30 and the rotation speed N2 and torque T2 of the second member 40 when it is desired to output the rotation speed N3=100 rpm and torque T3=1 Nm of the third member 50 (output shaft 60).

[0062] When the same output is taken out from the third member 50 (output shaft 60), since multiple combinations are possible, it is necessary to control the rotation speed N2 and torque T2 of the second member 40 according to the rotation speed N1 and torque T1 of the first member 30. Specifically, for example, the rotation speed N1 of the first member 30, the rotation speed N2 of the second member 40, and the rotation speed N3 of the third member 50 (output shaft 60) are measured using an encoder (not shown). In addition, the N1-T1 characteristic representing the relationship between the rotation speed N1 and torque T1 of the first member 30, and the N2-T2 characteristic representing the relationship between the rotation speed N2 and torque T2 of the second member 40 are obtained by separately measuring. This can be confirmed by measuring the state in which only the vibration type actuator 10 and the first member 30 are combined, or the characteristics of the electromagnetic motor 20 alone. The characteristics of the second member 40 can be converted from the characteristics of the electromagnetic motor 20 alone using the gear ratio between the pinion gear 70 and the spur gear 41. Then, the rotation speed N1 of the first member 30 and the rotation speed N2 of the second member 40 are controlled so as to achieve the desired rotation speed N3 of the third member 50 (output shaft 60). The rotation speed N3 of the third member 50 (output shaft 60) can be derived from equation (2), but since it is possible that the rolling elements 80 slip between the first member 30 and the third member 50, it is desirable to also measure the rotation speed N3 of the third member 50 (output shaft 60).

[0063] Furthermore, if the vibration actuator 10 stops due to a malfunction or the like and is driven only by the electromagnetic motor 20, a difference occurs between the amount of movement of the electromagnetic motor 20 and the amount of movement of the output shaft 60 due to backlash between the pinion gear 70 and the spur gear 41. For this reason, in order to know the amount of movement of the output shaft 60, an encoder is required for each of the first member 30, the second member 40, and the third member 50 (output shaft 60).

[0064] In this embodiment, the configuration has been described in which the first member 30 is driven by the vibration actuator 10, and the second member 40 is driven by the electromagnetic motor 20. The rotation of the first member 30 is transmitted as power to the third member 50 and the output shaft 60 by the rolling of the rolling body 80, so that a minute positional deviation corresponding to backlash does not occur unless the rolling body 80 slips. The rotation of the second member 40 generates a minute deviation when it is transmitted as power to the third member 50 and the output shaft 60 because there is a gap (backlash) between the hole 42 and the rolling body 80. Therefore, by using the vibration actuator 10 to drive the first member 30, which does not generate backlash when transmitting power to the third member 50, the advantages of the vibration actuator 10 can be utilized. In addition, by using the electromagnetic motor 20, which has a large output per unit volume, to drive the second member 40, it is possible to make the driving device 100-11 small in size and large in output.

[0065] Fig. 8 is a perspective view showing a second example of the schematic configuration of the drive device 100 according to the first embodiment. The drive device 100 according to the second example of the first embodiment shown in Fig. 8 is referred to as "drive device 100-12." In Fig. 8, the same components as those shown in Figs. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0066] The driving device 100-11 shown in FIG. 1 uses the spur gear 41 and the pinion gear 70 of the second member 40 as a driving force transmission means between the electromagnetic motor 20 and the second member 40. In contrast, the driving device 100-12 shown in FIG. 8 uses a second member 140 provided with a timing pulley 141 instead of the second member 40 shown in FIG. 1, and uses a timing pulley 170 instead of the pinion gear 70 shown in FIG. 1. The driving device 100-12 shown in FIG. 8 is newly provided with a timing belt 171, and transmits the driving force of the electromagnetic motor 20 to the second member 140 provided with the timing pulley 141 via the timing pulley 170 and the timing belt 171. With this configuration, the driving device 100-12 shown in FIG. 8 can align the driving direction of the electromagnetic motor 20 and the driving direction of the second member 140. This can prevent the driving device 100-12 from moving in the opposite direction to the driving direction of the electromagnetic motor 20 due to the counter torque of the electromagnetic motor 20. In the configuration of the driving device 100-12 shown in FIG. 8, backlash due to gears does not need to be considered, but since the driving force is transmitted by the timing belt 171, the driving device 100 becomes larger than the driving device 100-11 shown in FIG. 1 that uses gears. In this embodiment, the timing belt 171 is not limited to the timing belt, and other means may be used as long as they are made of a belt-like material that transmits the driving force. For example, a toothless pulley belt and pulley, or a chain such as a ladder chain may be used.

[0067] 1 and 8 show an example in which one vibration actuator 10 is provided to drive the first member 30, but this is not limited to the present embodiment. In the driving device 100 according to this embodiment, a plurality of vibration actuators 10 may be provided to drive the first member 30. Similarly, in the driving device 100-11 shown in FIG. 1 and 8 show an example in which one electromagnetic motor 20 is provided to drive the second member, but a plurality of electromagnetic motors 20 may be provided to drive the second member.

[0068] Fig. 9 is a cross-sectional view showing a third example of the schematic configuration of the drive device 100 according to the first embodiment. The drive device 100 according to the third example of the first embodiment shown in Fig. 9 is referred to as "drive device 100-13." In Fig. 9, the same components as those shown in Figs. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0069] The driving device 100-13 shown in Fig. 9 differs from the driving device 100-11 shown in Fig. 2 in the position and direction in which the vibration actuator 10 is disposed. Specifically, in the driving device 100-13 shown in Fig. 9, the vibration actuator 10 is disposed so as to be in pressure contact with the first member 30 from the radial direction.

[0070] The driving device 100 according to the first embodiment described above includes an output shaft 60, a first member 30 and a second member 40 configured to be rotatable with respect to the output shaft 60, and a third member 50 fixed to the output shaft 60. Furthermore, the driving device 100 according to the first embodiment includes a vibration actuator 10 that rotates the first member 30 around the output shaft 60, and an electromagnetic motor 20 that rotates the second member 40 around the output shaft 60. Furthermore, the driving device 100 according to the first embodiment includes a rolling element 80 that is rotatably held by the second member 40 and is sandwiched in contact with the first member 30 and the third member 50. In the driving device 100 according to the first embodiment, the third member 50 and the output shaft 60 rotate together by driving at least one of the vibration actuator 10 and the electromagnetic motor 20. According to this configuration, the driving forces of the multiple driving means (the vibration actuator 10 and the electromagnetic motor 20) can be added together without the driving of each of them becoming a load on each other. For example, the electromagnetic motor 20 is not driven by friction like the vibration actuator 10, so it is unlikely to become a load on the vibration actuator 10. Also, the third member 50 and the output shaft 60 can be rotated integrally even when only the vibration actuator 10 is driven, and the third member 50 and the output shaft 60 can be rotated integrally even when only the electromagnetic motor 20 is driven, so that the respective driving forces can be added together.

[0071] In the driving device 100 according to the first embodiment, the vibration actuator 10 rotates the first member 30 around the output shaft 60, and the electromagnetic motor 20 rotates the second member 40 around the output shaft 60, but the present invention is not limited to this. In the present invention, the vibration actuator 10 also includes a configuration in which one of the first member 30 and the second member 40 is rotated around the output shaft 60. Similarly, in the present invention, the electromagnetic motor 20 also includes a configuration in which the other member different from the one of the first member 30 and the second member 40 is rotated around the output shaft 60.

[0072] Second embodiment Next, a second embodiment will be described. In the following description of the second embodiment, matters common to the first embodiment will be omitted, and only matters different from the first embodiment will be described.

[0073] Fig. 10 is a perspective view showing an example of a schematic configuration of a drive device 100 according to a second embodiment. The drive device 100 according to the second embodiment shown in Fig. 10 is described as "drive device 100-2." In Fig. 10, the same components as those shown in Figs. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0074] The vibration actuator 10 according to the first embodiment shown in Figures 1 to 3 and 8 to 9 has a rectangular shape, but the vibration actuator 210 according to the second embodiment shown in Figure 10 has a circular ring shape.

[0075] 10, the vibration actuator 210 is in pressure contact with the first member 230 using a pressure means (not shown). When a traveling wave vibration is excited in the vibration actuator 210, a driving force is generated in the vibration actuator 210, and the driving force drives the first member 230, so that the first member 230 moves relative to the vibration actuator 210.

[0076] 10 has a configuration in which an elastic body 211 having a plurality of grooves 211a and a piezoelectric body 212, which is an electromechanical conversion element, are attached by adhesive or the like. By applying an alternating current to the piezoelectric body 212 from a flexible substrate (not shown) or the like, traveling wave vibration is excited in the vibration actuator 210, generating a driving force, and the first member 230 moves relatively to the vibration actuator 210.

[0077] The driving device 100 according to the second embodiment can use a circular annular vibration-type actuator 210 that generally has a larger output than the driving device 100 according to the first embodiment.

[0078] (Third embodiment) Next, a third embodiment will be described. In the following description of the third embodiment, the description of the matters common to the first and second embodiments will be omitted, and only the matters different from the first and second embodiments will be described.

[0079] In the third embodiment, an example will be described in which a camera platform device (rotating device) in an imaging device such as a surveillance camera is used as an apparatus including the driving device 100 described in the first and second embodiments.

[0080] Fig. 11 shows a third embodiment, and is a diagram showing an example of a schematic configuration of a pan head device 300 including a plurality of driving devices 100 described in the first and second embodiments. The pan head device 300 shown in Fig. 11(a) and the pan head device 300 shown in Fig. 11(b) are views of the pan head device 300 according to the third embodiment, viewed from different directions. For example, Fig. 11(a) is a view of the pan head device 300 viewed from the front, and Fig. 11(b) is a view of the pan head device 300 viewed from the side.

[0081] As shown in FIGS. 11(a) and 11(b), the pan head device 300 includes two driving devices 100-P and 100-T, a head unit 310, a base unit 320, an L-angle unit 330, and an imaging device 340.

[0082] 11(a), the head unit 310 includes two drive devices 100, a drive device 100-P for panning and a drive device 100-T for tilting. The base unit 320 is a component that supports the head unit 310. The L-angle unit 330 is attached to the head unit 310 and is a component for fixing the imaging device 340.

[0083] The panning driver 100-P can be either the driver 100-1 according to the first embodiment or the driver 100-2 according to the second embodiment. The panning driver 100-P has an output shaft 60 connected to a base unit 320, and is a driver for rotating the head unit 310, the L-angle unit 330, and the imaging device 340 around a pan axis relative to the base unit 320.

[0084] The tilt driving device 100-T can be either the driving device 100-1 according to the first embodiment or the driving device 100-2 according to the second embodiment. The tilt driving device 100-T has an output shaft 60 connected to the L-angle unit 330, and is a driving device for rotating the L-angle unit 330 and the imaging device 340 around the tilt axis relative to the head unit 310.

[0085] Imaging device 340 attached to L-angle portion 330 is a camera for taking moving and still images, and is capable of panning and tilting by driving two driving devices 100-P and 100-T while taking images.

[0086] The driving device 100 according to the third embodiment can be used as a driving source for the pan head device 300.

[0087] It should be noted that the above-mentioned embodiments of the present invention are merely illustrative examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0088] Disclosure of embodiments of the present invention includes the following configurations and methods. [Configuration 1] An output shaft; A first member and a second member configured to be rotatable relative to the output shaft; A third member fixed to the output shaft; a vibration actuator that rotates one of the first member and the second member around the output shaft; an electromagnetic motor that rotates one of the first member and the second member, the other of the first member and the second member being different from the other of the first member and the second member, about the output shaft; a rolling element rotatably held by the second member and sandwiched between the first member and the third member; Equipped with When at least one of the vibration actuator and the electromagnetic motor is driven, the third member and the output shaft rotate together. A drive device characterized by: [Configuration 2] The third member and the output shaft rotate integrally via the rolling elements when the at least one of them is driven. 2. The drive device according to claim 1, [Configuration 3] The first member, the second member, and the third member are each inserted through the output shaft. 3. The drive device according to configuration 1 or 2. [Configuration 4] When the vibration actuator and the electromagnetic motor are driven together, the third member and the output shaft rotate integrally. 4. The drive device according to any one of configurations 1 to 3. [Configuration 5] When one of the vibration actuator and the electromagnetic motor becomes unable to operate, the other can be operated independently. 5. The drive device according to any one of configurations 1 to 4. [Configuration 6] A rotation speed of the first member is defined as N1 when the first member rotates counterclockwise with respect to the axial direction of the output shaft as a positive rotation speed, When the second member rotates counterclockwise with respect to the axial direction of the output shaft as a reference, the number of rotations of the second member is defined as N2. N2 / N1>0.5 is satisfied 6. The drive device according to any one of configurations 1 to 5. [Configuration 7] In the above N1 and N2, N2≧N1 is satisfied. 7. The drive device according to claim 6, [Configuration 8] The torque of the first member is defined as T1, and the torque of the first member is defined as T2 when the first member rotates counterclockwise with respect to the axial direction of the output shaft as a positive torque. When the torque of the second member is T2, the torque T2 satisfies the following formula (A):

number

[0089] 10,210: vibration type actuator, 11,211: elastic body, 11a,11b: protrusion, 12,212: piezoelectric body, 13: vibrating body, 14: cushioning member, 15: pressure transmission member, 16: vibrating body support part, 20: electromagnetic motor, 30,230: first member, 40,140: second member, 41: spur gear, 42: hole, 50: third member, 60: output shaft, 70: pinion gear, 80: rolling body, 90: exterior part, 91-94: bearings, 100: driving device, 141: timing pulley, 170: timing pulley, 171: timing belt, 300: pan head device, 310: head part, 320: base part, 330: L angle part, 340: imaging device, L: rotation axis

Claims

1. An output shaft; A first member and a second member configured to be rotatable about the output shaft; A third member fixed to the output shaft; a vibration actuator that rotates one of the first member and the second member around the output shaft; an electromagnetic motor that rotates one of the first member and the second member, the other of the first member and the second member being different from the other of the first member and the second member, about the output shaft; a rolling element rotatably held by the second member and sandwiched between the first member and the third member; Equipped with When at least one of the vibration actuator and the electromagnetic motor is driven, the third member and the output shaft rotate integrally. A drive device characterized by:

2. The third member and the output shaft rotate integrally via the rolling elements when the at least one of them is driven.

2. The drive device according to claim 1 .

3. The first member, the second member, and the third member are each inserted through the output shaft.

2. The drive device according to claim 1 .

4. When the vibration actuator and the electromagnetic motor are driven together, the third member and the output shaft rotate integrally.

2. The drive device according to claim 1 .

5. When one of the vibration actuator and the electromagnetic motor becomes unable to operate, the other can be operated independently.

2. The drive device according to claim 1 .

6. A rotation speed of the first member is defined as N1 when the first member rotates counterclockwise with respect to the axial direction of the output shaft as a positive rotation speed, When the rotation speed of the second member is defined as N2, the rotation speed of the second member is defined as N2 when the rotation speed of the second member is positive with respect to the axial direction of the output shaft as a reference. N2 / N1>0.5 is satisfied 2. The drive device according to claim 1 .

7. In the N1 and the N2, N2≧N1 is satisfied.

7. The drive device according to claim 6.

8. The torque of the first member is defined as T1, and the torque of the first member is defined as T2 when the first member rotates counterclockwise with respect to the axial direction of the output shaft as a positive torque. When the torque of the second member is T2, the torque T2 satisfies the following formula (A): [0010] 7. The drive device according to claim 6.

9. The vibration actuator is rectangular or annular.

2. The drive device according to claim 1 .

10. The vibration actuator is provided in plurality.

2. The drive device according to claim 1 .

11. The vibration actuator rotates the first member around the output shaft, The electromagnetic motor drives the second member to rotate about the output shaft.

2. The drive device according to claim 1 .

12. The rolling elements are spherical, cylindrical or columnar.

2. The drive device according to claim 1 .

13. The rolling element includes a gear, The first member and the third member have teeth formed at their locations in contact with the gear.

2. The drive device according to claim 1 .

14. An output shaft; A first member and a second member configured to be rotatable about the output shaft; A third member fixed to the output shaft; a vibration actuator that rotates one of the first member and the second member around the output shaft; an electromagnetic motor that rotates one of the first member and the second member, the other of the first member and the second member being different from the other of the first member and the second member, about the output shaft; a rolling element rotatably held by the second member and sandwiched between the first member and the third member; A method for driving a drive device comprising: When at least one of the vibration actuator and the electromagnetic motor is driven, the third member and the output shaft rotate integrally. A driving method comprising:

Images