Drive unit

Abstract

To improve storage property of a driving device having a leaf spring which presses a lead screw, and fixability of the leaf spring.SOLUTION: A driving device 1 comprises: a frame 2 having a first wall 2b and a second wall 2c which are opposed to each other; a driving section 3 provided in the frame 2 at the side of the first wall 2b; a lead screw 4 which is rotated by drive power of the driving section 3; a bearing 8 which is at least partially provided on an opposite surface 2e of the second wall 2c, which is opposed with the first wall 2b, and supports the lead screw 4 rotatably; a movable member 6 which is moved along the lead screw 4 by the drive power of the driving section 3; and a leaf spring 7 which has a stationary part 7a and a power application part 7b. The leaf spring 7 is fixed to the second wall 2c by holding the stationary part 7a between the second wall 2c and at least a part of the bearing 8, and the power application part 7b presses an end of the lead screw 4 at the side of the second wall 2c toward the side of the first wall 2b.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a driving device.

Background Art

[0002] Conventionally, driving devices with various configurations that move a movable member along a lead screw by the driving force of a driving unit have been used. Among these, there is a driving device having a leaf spring that presses the lead screw. For example, Patent Document 1 discloses a stepping motor that can move a connecting portion along a lead screw by the driving force of a driving unit and presses the lead screw with a thrust spring.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional driving device having a leaf spring that presses a lead screw, the fixity of the leaf spring may be insufficient. For example, the thrust spring of Patent Document 1 has a configuration in which only the clip portion of the leaf spring is hooked on the frame, so it cannot be said that the fixity is sufficient. Further, in a conventional driving device, in order to improve the fixity of the leaf spring, the structure of the leaf spring and its fixing portion becomes complicated and large-sized, and also, since the entire leaf spring is arranged outside the frame and the arrangement of the leaf spring is not good, the storage property of the driving device may decrease.

Means for Solving the Problems

[0005] The drive device of the present invention comprises a frame having opposing first and second walls, a drive unit provided on the first wall side of the frame, a lead screw extending from the first wall to the second wall and rotated by the drive unit by a driving force, a bearing provided on at least a portion of the opposing surface of the second wall facing the first wall and rotatably supporting the lead screw, a movable member that moves along the lead screw by the driving force of the drive unit, a fixed portion, and a leaf spring having a force-applying portion that faces the fixed portion and applies force in a direction approaching and moving away from the fixed portion, wherein the leaf spring is fixed to the second wall by the fixed portion being sandwiched between the second wall and at least a portion of the bearing, and the force-applying portion is configured to press the end of the lead screw on the second wall side toward the first wall side. [Effects of the Invention]

[0006] The present invention can improve the storability and stability of a leaf spring in a drive device having a leaf spring that presses against a lead screw. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing the drive unit of this embodiment. [Figure 2] This is a perspective view of the drive unit shown in Figure 1, taken from a different angle than in Figure 1. [Figure 3] Figure 1 is a perspective view showing the joint between the bearing and the leaf spring of the drive unit. [Figure 4] Figure 1 is a perspective view showing the bearings of the drive unit. [Figure 5] Figure 1 is a perspective view showing the leaf spring of the drive mechanism. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. First, a drive device 1, which is one embodiment of the present invention, will be described with reference to Figures 1 and 2. Figures 1 and 2 are perspective views showing the drive device 1 of this embodiment. In the following description, the axial direction of the lead screw 4 will be defined as the X direction, and the directions perpendicular to the X direction and mutually perpendicular will be defined as the Y direction and Z direction. The drive device 1 of this embodiment can be applied, for example, to a head-up display device for a vehicle. However, the present invention is not limited to a drive device applicable to a head-up display device for a vehicle.

[0009] The drive unit 1 comprises a lead screw 4 with a helical groove formed on its outer surface, a drive unit 3 for rotationally driving the lead screw 4 around its axis, a movable member 6 that engages with the helical groove and moves in the direction of axis A, and a frame 2 that supports the drive unit 3 and the like. The frame 2 has a plate-shaped frame body 2a and a pair of walls, a first wall 2b and a second wall 2c, which are formed by bending both ends of the frame body 2a in the longitudinal direction so that they face each other.

[0010] Guide shafts 5A and 5B are fixed to the first wall 2b and second wall 2c of frame 2 as guide shafts 5, which are arranged parallel to the lead screw 4 in the X direction. Guide shafts 5 engage with a mirror holder or the like attached to the movable member 6, and enable the movable member 6 to move along the lead screw 4 while suppressing the rotation of the movable member 6 in conjunction with the rotation of the lead screw 4.

[0011] The drive unit 3 is a motor such as a stepping motor, and is generally composed of a stator 14 that constitutes the motor case and a rotor (not shown) located inside the stator 14. The rotor is equipped with a lead screw 4 and a permanent magnet (not shown) fixed to the lead screw 4.

[0012] The stator 14 is fixed to the first wall 2b of the frame 2 by welding or the like. The power supply board 10 is fixed to this first wall 2b, for example, by bolts. Terminal pins, which serve as the power supply section, are provided on the side of the stator 14 and are electrically connected to the power supply board 10. The end portion of the drive coil (not shown) of the stator 14 is wrapped around the terminal pins, and by soldering the terminal pins to the power supply board 10, an electrical connection can be made between the power supply board 10 and the drive coil.

[0013] Furthermore, a switch unit can be attached to the power supply board 10. For example, a push-type switch that detects the origin position in the direction of movement of the movable member 6 can be attached as the switch unit. The electrical connection between the switch unit and the power supply board 10 is made by soldering the terminal pins of the switch unit to the power supply board 10.

[0014] The lead screw 4 is rotationally driven by the drive unit 3. The lead screw 4 is positioned approximately parallel to the frame body 2a, and its end in the +X direction (the direction of the arrow tip in the X direction) is rotatably supported by a bearing 8 attached to a hole 2d in the second wall 2c of the frame 2 via a washer 9. A leaf spring 7 is attached between the second wall 2c and the bearing 8 in the X direction. The leaf spring 7 biases the +X end of the lead screw 4 toward the -X direction (the direction of the arrow trailing off in the X direction). The detailed configuration of the leaf spring 7 and how it is attached to the frame 2 will be described later.

[0015] Here, the -X-direction end of the lead screw 4 has a hemispherical protrusion structure, and the drive unit side bearing portion 3a that receives the -X-direction end of the lead screw 4 has a hemispherical recess structure. Therefore, by biasing the lead screw 4 toward the -X direction, not only is the position of the lead screw 4 in the X direction determined, but the position in the direction intersecting the X direction is also determined, and rotational wobble of the lead screw 4 when it is rotated can be reduced.

[0016] In this embodiment, the drive unit 1 is configured to bias the lead screw 4 toward the side where the drive unit 3 is located, from the side opposite to the side where the drive unit 3 is located. Conversely, it is also possible to configure the drive unit 1 in such a way that the lead screw 4 is biased toward the side opposite to the side where the drive unit 3 is located. However, by configuring the drive unit 1 in this embodiment to bias the lead screw 4 toward the side where the drive unit 3 is located from the side opposite to the side where the drive unit 3 is located, it becomes possible to position the biasing mechanism for the lead screw 4 farther away from the drive unit 3. By positioning the biasing mechanism for the lead screw 4 farther away from the drive unit 3, the distance to the leaf spring 7, which is prone to vibration due to the rotation of the lead screw 4, can be increased.

[0017] Here, the leaf spring 7 also plays a role in pressing the lead screw 4 to one side in the radial direction. When pressing the lead screw 4, if it is positioned on the side of the drive unit 3, a stronger biasing force is required compared to when it is distributed on the opposite side from the drive unit 3. In other words, a smaller biasing force is sufficient when it is positioned on the opposite side from the drive unit 3. Note that the biasing force in the radial direction is to prevent the impact noise described below, and the biasing force in the axial direction (X-axis direction) is to suppress the axial movement (movement) of the magnet.

[0018] The lead screw 4 is held (inserted) by bearings 7 at both ends in the X-axis direction, but there is a slight gap between the outer surface of the lead screw 4 and the inner surface of the bearings 7 as the lead screw 4 rotates. When the lead screw 4 rotates normally, its outer circumference always rotates along the inner surface of the bearings 7, but it is possible that the lead screw 4 may temporarily separate from the bearings 7 during rotation. Then, when the lead screw 4 and the bearings 7 come into contact again, an impact noise is generated. For this reason, the biasing force of the leaf spring 7 presses the lead screw 4 to one side in order to prevent it from separating from the inner surface of the bearings 7.

[0019] The movable member 6 can be attached with, for example, a mirror holder that holds a mirror used in a head-up display device for a vehicle or the like. By attaching a mirror holder that holds a mirror to the movable member 6, the drive unit 3 is driven to rotate the lead screw 4, and the mirror holder and the mirror held by the mirror holder can be moved along the X direction together with the movable member 6.

[0020] Next, mainly referring to FIGS. 3 to 5, the detailed configuration of the leaf spring 7 and the bearing 8, and how the leaf spring 7 is attached to the second wall 2c by the bearing 8 will be described. Here, FIG. 3 is a perspective view showing the joint portion between the bearing 8 and the leaf spring 7 of the drive device 1, FIG. 4 is a perspective view showing the bearing 8 of the drive device 1, and FIG. 5 is a perspective view showing the leaf spring 7 of the drive device 1. Note that FIGS. 3 to 5 are perspective views seen from substantially the same direction.

[0021] As shown in FIGS. 3 and 4, the bearing 8 has a first cylindrical portion 8a and a second cylindrical portion 8b. Then, as shown in FIG. 2, the first cylindrical portion 8a is attached to the circular hole portion 2d of the second wall 2c. By attaching the first cylindrical portion 8a to the hole portion 2d of the second wall 2c, the surface 8e on the +X direction side of the first cylindrical portion 8a will face in a state of contact with the second wall 2c.

[0022] Also, as shown in FIGS. 3 and 4, the bearing 8 is provided with a recess 8c that is recessed inward (toward the lead screw 4) at the end on the +X direction side (the surface 8e side) of the second cylindrical portion 8b. By attaching the first cylindrical portion 8a of the bearing 8 to the hole portion 2d of the second wall 2c, the recess 8c forms a groove whose side surfaces are formed by the surface 8d on the -X direction side of the recess 8c and the surface of the second wall 2c, that is, an inwardly recessed circumferential groove. The leaf spring 7 is attached to this groove.

[0023] More specifically, as shown in Figures 3 and 5, the leaf spring 7 is a flat plate-shaped member and includes a fixing portion 7a, a force-applying portion 7b that faces the fixing portion 7a and applies force in directions approaching and moving away from the fixing portion 7a, and a connecting portion 7c that connects the fixing portion 7a and the force-applying portion 7b. The fixing portion 7a has protrusions 7d and 7e that extend outward (opposite to the lead screw 4) in the same direction. In other words, the fixing portion 7a has a notch 7i cut out on the inside (lead screw 4 side). The leaf spring 7 is then attached to the groove such that the notch 7i, protrusions 7d and 7e are positioned inwardly recessed circumferential groove corresponding to the recess 8c, as shown in Figure 3. In this embodiment, the leaf spring 7 is constructed by bending a single flat plate-shaped member to form the fixing portion 7a, the force-applying portion 7b, and the connecting portion 7c. However, the configuration is not limited to this embodiment, as long as the force-applying portion 7b faces the fixing portion 7a and applies force in directions approaching and moving away from the fixing portion 7a.

[0024] As described above, the drive device 1 of this embodiment comprises a frame 2 having opposing first wall 2b and second wall 2c, a drive unit 3 provided on the first wall 2b side of the frame 2, a lead screw 4 extending from the first wall 2b to the second wall 2c and rotated by the driving force of the drive unit 3, and a movable member 6 moving along the lead screw 4 by the driving force of the drive unit 3. Furthermore, as shown in Figure 1, it comprises a bearing 8 provided at least in part on the opposing surface 2e of the second wall 2c facing the first wall 2b, which rotatably supports the lead screw 4, and a leaf spring 7 having a fixed part 7a and a force-applying part 7b. In the drive device 1 of this embodiment, the leaf spring 7 is fixed to the second wall 2c by the fixed part 7a being sandwiched between the second wall 2c and the surface 8d of a recess 8c which is part of the bearing 8, and the force-applying part 7b is configured to press the end of the lead screw 4 on the second wall 2c side toward the first wall 2b side.

[0025] As in this embodiment, by configuring the fixing portion 7a of the leaf spring 7 to be sandwiched between the second wall 2c and at least a part of the bearing 8, thereby fixing the leaf spring 7 to the frame 2, the leaf spring 7 can be firmly fixed to the frame 2, improving the fixation of the leaf spring 7 to the frame 2. Furthermore, as in this embodiment, by fixing the fixing portion 7a of the leaf spring 7 to the opposing surface 2e of the second wall 2c, the drive unit 1 can be miniaturized by the thickness of the second wall 2c (thickness in the X direction), improving the storage capacity of the drive unit 1.

[0026] In this embodiment, as shown in Figure 3, the leaf spring 7 is fixed to the second wall 2c by being sandwiched between the surface 8d of the bearing 8 for a semicircular portion along its circumference. This method of fixing by being sandwiched along the circumference makes it less prone to displacement, and the fixing force is particularly improved by being sandwiched for more than a semicircular portion. In this embodiment, it is fixed along the circumference of a nearly perfect circle, but it may also be fixed along the circumference of an ellipse instead of a perfect circle.

[0027] Furthermore, as described above, in the drive device 1 of this embodiment, the bearing 8 has a recess 8c on the second wall 2c side that is recessed inward (towards the lead screw 4 side). The leaf spring 7 has a notch 7i in its fixing portion 7a. The notch 7i fits into the recess 8c, so that the fixing portion 7a of the leaf spring 7 is sandwiched between the second wall 2c and the surface 8d of the recess 8c on the first wall 2b side. With this configuration, the leaf spring 7 can be easily attached to the frame 2 by inserting the notch 7i into the recess 8c, and the fixing portion 7a of the leaf spring 7 can be firmly fixed between the second wall 2c and the surface 8d of the recess 8c on the first wall 2b side. Moreover, by configuring the notch 7i to be inserted into the recess 8c and by configuring the notch 7i to be in contact with the recess 8c for positioning, the positioning accuracy of the leaf spring 7 relative to the frame 2 can be increased.

[0028] Furthermore, in the drive device 1 of this embodiment, as shown in Figures 1 to 3 and Figure 5, the leaf spring 7 has a bent portion 7j that is bent at approximately 90° relative to the fixed portion 7a on the opposite side of the open side of the notch portion 7i in the fixed portion 7a. By having such a bent portion 7j, for example, a user can insert the notch portion 7i into the recess 8c by pressing the bent portion 7j with their hand. That is, the notch portion 7i can be inserted into the recess 8c without touching the connection portion 7c between the fixed portion 7a and the force-applying portion 7b. In particular, in the drive device 1 of this embodiment, when inserting the notch portion 7i into the recess 8c, the user can easily insert the notch portion 7i into the recess 8c by simultaneously pressing the bent portion 7j and the shoulder portion 7h. There is a risk that the performance of the leaf spring 7 may deteriorate if force is applied to the connection portion 7c between the fixed portion 7a and the force-applying portion 7b and the angle between the fixed portion 7a and the force-applying portion 7b changes, but this risk can be suppressed. In this embodiment, only one folded portion 7j is provided, but for example, another folded portion may be provided at the shoulder portion 7h.

[0029] Furthermore, because the leaf spring 7 has a bent portion 7j, when the leaf spring 7 is removed from the frame 2, the user can hold the bent portion 7j by hand, making it easy to carry the leaf spring 7. In this embodiment of the leaf spring 7, the bent portion 7j is bent at approximately 90° relative to the fixing portion 7a, but there are no particular limitations on the bending angle. In this embodiment, the leaf spring 7 can be fitted to the frame 2 last after all the above components other than the leaf spring 7, such as the lead screw 4 and bearing 8, have been assembled, but the configuration is not limited to this. Alternatively, the leaf spring 7 may be assembled to the frame 2 and then the fixing portion 7a of the leaf spring 7 may be sandwiched together with the second wall 2c by the bearing 8.

[0030] Furthermore, in the drive device 1 of this embodiment, the bent portion 7j is in contact with a part of the end of the second wall 2c by the notch portion 7i fitting into the recess 8c. In this way, it is preferable that the bent portion 7j is positioned by contacting at least a part of the second wall 2c by the notch portion 7i fitting into the recess 8c. This is because the leaf spring 7 can be accurately positioned relative to the frame 2 with a simple structure.

[0031] Furthermore, as shown in Figures 3 and 5, in the drive device 1 of this embodiment, the leaf spring 7 has projections 7g and 7k that contact the recess 8c when the notch 7i is fitted into the recess 8c. In the leaf spring 7 of the drive device 1 of this embodiment, as the notch 7i is fitted into the recess 8c, the projections 7d and 7e bend, spreading outwards and then narrowing inwards again. As shown in Figures 3 and 5, the projection 7g is provided on the projection 7d, and the projection 7k is provided on the projection 7e. By having the projection 7g on the projection 7d and the projection 7k on the projection 7e in this way, it is possible to prevent the leaf spring 7, which has been fitted into the recess 8c, from coming out of the recess 8c unintentionally.

[0032] Furthermore, as shown in Figures 1 and 2, the drive device 1 of this embodiment includes guide shafts 5A and 5B, which are shafts connected to the first wall 2b and the second wall 2c. And, as shown in Figures 1, 3 and 5, the leaf spring 7 has a contact portion 7f on its fixed portion 7a that comes into contact with the guide shaft 5A when it rotates in conjunction with the rotation of the lead screw 4. Therefore, it is possible to suppress the rotation of the leaf spring 7 in conjunction with the rotation of the lead screw 4.

[0033] The present invention is not limited to the embodiments described above, and can be realized in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

[0034] Finally, the present invention is described comprehensively below.

[0035] (1) A drive device comprising: a frame having opposing first and second walls; a drive unit provided on the first wall side of the frame; a lead screw extending from the first wall to the second wall and rotated by the drive unit by a driving force; a bearing provided on at least a portion of the opposing surface of the second wall facing the first wall and rotatably supporting the lead screw; a movable member that moves along the lead screw by the driving force of the drive unit; a fixed portion; and a leaf spring having a force-applying portion that faces the fixed portion and applies force in a direction approaching and moving away from the fixed portion, wherein the leaf spring is fixed to the second wall by the fixed portion being sandwiched between the second wall and at least a portion of the bearing, and the force-applying portion is configured to press the end of the second wall of the lead screw toward the first wall.

[0036] (2) The drive device described in (1) above, wherein the bearing has a recess on the second wall side that is recessed on the lead screw side, and the leaf spring has a notch in the fixed part, and is configured such that the notch fits into the recess and is sandwiched between the second wall and the surface of the recess on the first wall side.

[0037] (3) The drive device described in (2) above, wherein the leaf spring has a bent portion that is bent relative to the fixing portion on the side opposite to the open side of the notch in the fixing portion.

[0038] (4) The drive device described in (3) above, wherein the bent portion is in contact with at least a part of the second wall by the notch portion fitting into the recess.

[0039] (5) A drive device according to any one of (2) to (4) above, characterized in that the leaf spring has a projection that contacts the recess when the notch is fitted into the recess.

[0040] (6) A drive device according to any one of (1) to (5) above, wherein the drive device comprises a shaft connected to the first wall and the second wall, and the leaf spring has a contact portion in the fixed portion that contacts the shaft when it rotates in conjunction with the rotation of the lead screw. [Explanation of symbols]

[0041] 1…Drive unit, 2…Frame, 2a…Frame body, 2b…First wall, 2c…Second wall, 2d…Hole, 2e…Opposite surface, 3…Drive unit, 3a…Drive unit side bearing part, 4…Lead screw, 5…Guide shaft, 5A…Guide shaft (shaft), 5B…Guide shaft (shaft), 6…Movable member, 7…Leaf spring, 7a…Fixed part, 7b…Force applying part, 7c…Connecting part, 7d…Protrusion, 7e…Protrusion, 7f…Contact part, 7g…Projection, 7h…Shoulder part, 7i…Notch, 7j…Bending part, 7k…Protrusion, 8…Bearing, 8a…First cylindrical part, 8b…Second cylindrical part, 8c…Recess, 8d…Surface, 8e…Surface, 9…Washer, 10…Power supply board, 14…Stator

Claims

1. A frame having opposing first and second walls, The drive unit provided on the first wall side of the frame, A lead screw extending from the first wall to the second wall and rotating by the driving force of the drive unit, A bearing is provided on at least a portion of the opposing surface of the second wall facing the first wall, and rotatably supports the lead screw. A movable member that moves along the lead screw by the driving force of the drive unit, A leaf spring having a fixed part and a force-applying part that faces the fixed part and applies force in a direction approaching and away from the fixed part, Equipped with, The leaf spring is fixed to the second wall by the fixing portion being sandwiched between the second wall and at least a part of the bearing, and the force-applying portion is configured to press the end of the lead screw on the second wall side toward the first wall side. The bearing has a recess on the second wall side that is recessed on the lead screw side, The leaf spring has a notch in the fixing portion, and is configured such that the notch fits into the recess, causing it to be sandwiched between the second wall and the surface of the recess on the first wall side. The leaf spring has a bent portion on the side of the fixing portion opposite to the open side of the notch portion, which is bent relative to the fixing portion. The drive device is characterized in that the bending portion is provided outside the range of the area in the fixing portion that is connected to the force-applying portion.

2. In the drive device according to claim 1, The drive device is characterized in that the bent portion comes into contact with at least a part of the second wall by the notch portion fitting into the recess.

3. In the drive device according to claim 1, The drive device is characterized in that the leaf spring has a projection that contacts the recess when the notched portion is fitted into the recess.

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