CN114076188A - Drive device - Google Patents

Abstract

The invention provides a driving device. The driving device comprises: a rack gear extending in the driving direction and provided with a tooth surface on an upper surface side; a gear motor having a motor main body, a transmission mechanism connected to the motor main body, and a pinion gear engaged with the rack gear, the pinion gear being connected to the transmission mechanism and rotating around a central axis; and a frame that slidably supports the rack and pinion. The frame has a guide surface that guides the rack gear from one side in the vertical direction and restricts the rack gear from moving to one side in the vertical direction. The rack gear has an opposed surface opposed to the guide surface and extending in the driving direction. The facing surface is provided with a groove extending in the driving direction or recessed steps located at both edges in the width direction and extending in the driving direction.

Description

Drive device

Technical Field

The present invention relates to a drive device.

Background

In recent years, electronic devices such as smart phones have been increasingly thinned, and high output is demanded for mounted gearmotors. Patent document 1 discloses a high-output gear box device mounted on such a thin electronic device.

Patent document 1: japanese patent laid-open publication No. 2019-47589

The driving device adopts the following structure: when the driving object is moved in parallel, the rotation of the motor is converted into parallel motion by using the output portion as a rack and pinion. The rack gear is slidably supported by the frame, for example. The rack gear is provided with an opposing surface that slides while opposing the frame-side guide surface. When the molding accuracy of the facing surface is low, the sliding efficiency of the rack and pinion may be reduced.

Disclosure of Invention

An object of one embodiment of the present invention is to provide a driving device capable of improving sliding efficiency of a rack gear.

One embodiment of the present invention is a driving device including: a rack gear extending in the driving direction and provided with a tooth surface on an upper surface side; a gear motor having a motor main body, a transmission mechanism connected to the motor main body, and a pinion gear engaged with the rack gear, the pinion gear being connected to the transmission mechanism and rotating around a central axis; and a frame that slidably supports the rack and pinion. The frame has a guide surface that guides the rack gear from one side in the vertical direction and restricts the rack gear from moving to one side in the vertical direction. The rack gear has an opposed surface opposed to the guide surface and extending in the driving direction. The facing surface is provided with a groove extending in the driving direction or recessed steps located at both edges in the width direction and extending in the driving direction.

According to one aspect of the present invention, a driving device capable of improving the sliding efficiency of a rack and pinion is provided.

Drawings

Fig. 1 is a perspective view of a driving device according to an embodiment.

Fig. 2 is a sectional view of a driving apparatus according to an embodiment.

FIG. 3 is an exploded view of one embodiment of a drive device.

Fig. 4 is a perspective view of the frame of the embodiment as viewed obliquely from below.

Fig. 5 is a sectional view of a driving device of an embodiment.

Fig. 6 is a sectional view of a driving device according to an embodiment.

Fig. 7 is a perspective view of a rack and pinion according to modification 1.

Fig. 8 is a perspective view of a rack and pinion according to modification 2.

Description of the reference symbols

1: a drive device; 2A, 2B: a gear motor; 3. 103, 203: a rack and pinion; 3 a: an upper surface; 3f, 103f, 203 f: opposite surfaces; 3g, 203 g: a groove; 3 k: a tooth surface; 3t, 103t, 203 t: a trace; 103 g: a step portion; 10: a frame; 13 f: a 1 st guide surface; 20A, 20B: a motor main body; 30A, 30B: a planetary gear mechanism (transmission mechanism); j1, J2: a central axis.

Detailed Description

Hereinafter, a driving device 1 according to an embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the following description, unless otherwise specified, the direction (Z-axis direction) parallel to the central axes J1, J2 is simply referred to as "axial direction", the + Z side is simply referred to as "one axial side", and the-Z side is simply referred to as "the other axial side". The circumferential direction around each of the center axes J1, J2 is simply referred to as the "circumferential direction", and the radial direction with respect to each of the center axes J1, J2 is simply referred to as the "radial direction".

For the sake of simplifying the description of the present specification, the Y-axis direction is simply referred to as the up-down direction, the + Y-axis direction is simply referred to as the upper side, and the-Y direction is simply referred to as the lower side. The vertical direction in this specification is a direction set for convenience of description, and does not limit the posture of the drive device 1 when used.

Fig. 1 is a perspective view of a driving device 1 according to an embodiment. Fig. 2 is a sectional view of the drive device 1. The drive device 1 of the present embodiment is mounted on a thin electronic device in which the dimension in the Y axis direction is suppressed.

As shown in fig. 1, the drive device 1 includes a 1 st gear motor 2A, a 2 nd gear motor 2B, a rack gear 3, a frame 10, and a fitting 40.

The 1 st and 2 nd gear motors 2A and 2B have a columnar shape extending in the Z-axis direction. The 1 st and 2 nd gear motors 2A and 2B are disposed adjacent to each other in the X axis direction.

As shown in fig. 2, the 1 st gear motor 2A extends along the 1 st central axis J1. In addition, the 2 nd gear motor 2B extends along the 2 nd central axis J2. The 1 st central axis J1 and the 2 nd central axis J2 extend parallel to each other.

The 1 st gear motor 2A includes a 1 st motor main body 20A, a 1 st planetary gear mechanism (1 st transmission mechanism) 30A connected to the 1 st motor main body 20A, and a 1 st pinion gear 5A connected to the 1 st planetary gear mechanism 30A. The motor shaft 29 of the 1 st motor main body 20A, the 1 st planetary gear mechanism 30A, and the 1 st pinion gear 5A rotate about the 1 st central axis J1.

Similarly, the 2 nd gear motor 2B includes a 2 nd motor main body 20B, a 2 nd planetary gear mechanism (2 nd transmission mechanism) 30B connected to the 2 nd motor main body 20B, and a 2 nd pinion gear 5B connected to the 2 nd planetary gear mechanism 30B. The motor shaft 29 of the 2 nd motor main body 20B, the 2 nd planetary gear mechanism 30B, and the 2 nd pinion gear 5B rotate about the 2 nd central axis J2.

The 1 st and 2 nd motor bodies 20A, 20B extend along the respective center axes (i.e., the 1 st center axis J1 or the 2 nd center axis J2). The 1 st and 2 nd motor bodies 20A and 20B are generally cylindrical with center axes J1 and J2 as centers. In the present embodiment, the 1 st and 2 nd motor main bodies 20A, 20B are stepping motors.

The 1 st and 2 nd motor main bodies 20A, 20B have a rotor 21 that rotates about respective center axes J1, J2, a stator 22 that surrounds the rotor 21 from the radial outside, and a motor case 23 that further surrounds the stator 22 from the radial outside. The rotor 21 has a motor shaft 29 extending along each of the center axes J1, J2.

The 1 st and 2 nd planetary gear mechanisms 30A, 30B are connected to the motor shafts 29 of the 1 st and 2 nd motor main bodies 20A, 20B, respectively. The 1 st and 2 nd planetary gear mechanisms 30A, 30B are speed reduction mechanisms that reduce the power output from the 1 st and 2 nd motor main bodies 20A, 20B and transmit the power to the 1 st and 2 nd pinion gears 5A, 5B, respectively. In the present embodiment, the reduction gear ratio of the 1 st planetary gear mechanism 30A and the reduction gear ratio of the 2 nd planetary gear mechanism 30B are equal to each other.

The 1 st and 2 nd planetary gear mechanisms 30A, 30B respectively have a gear housing 39, a 1 st sun gear 33a, 31 st planetary gears 33B, a 1 st carrier 31, 32 nd planetary gears 34B, a 2 nd carrier 32, 3 rd planetary gears 35B, and a 3 rd carrier 36.

The gear housing 39 is fixed to the frame 10. That is, the 1 st and 2 nd planetary gear mechanisms 30A, 30B are supported by the frame 10 in the gear housing 39. The gear housing 39 has an internal gear 39a and a bearing portion 39 d.

The internal gear 39a is cylindrical and extends in the axial direction around the central axes J1 and J2. The internally-toothed gear 39a meshes with the 1 st planetary gear 33b, the 2 nd planetary gear 34b, and the 3 rd planetary gear 35 b. The bearing portion 39d is located at the other axial end of the internal gear 39 a. The bearing portion 39d extends in a cylindrical shape around the center axes J1 and J2. A slide bearing is attached to the inner peripheral surface of the bearing 39 d. The bearing portion 39d rotatably supports a cylindrical portion 36f described later.

The 1 st sun gear 33a is fixed to the motor shaft 29 and rotates together with the motor shaft 29 about the central axes J1 and J2. The 31 st planetary gears 33b are arranged at equal intervals in the circumferential direction of the central axes J1, J2. The 31 st planetary gears 33b are meshed with the 1 st sun gear 33 a. The 31 st planetary gears 33b revolve around the respective center axes J1, J2 in accordance with the rotation of the 1 st sun gear 33 a.

The 1 st carrier 31 has a 1 st disc portion 31b, 31 st counter shafts 31a, and a 2 nd sun gear 31 c. The 1 st disc portion 31b extends in the radial direction around the central axes J1 and J2. The 31 st auxiliary shafts 31a extend from the 1 st disc portion 31b to one axial side. The 2 nd sun gear 31c extends from the 1 st disc portion 31b to the other axial side about the central axes J1, J2.

The 1 st planetary gear 33b is rotatably supported by the 31 st counter shafts 31 a. The 1 st carrier 31 rotates about the central axes J1, J2 in accordance with the revolving rotation of the 31 st planetary gears 33 b.

The 2 nd sun gear 31c is a part of the 1 st carrier 31, and therefore rotates about the central axes J1 and J2 in accordance with the revolving rotation of the 1 st planetary gear 33 b.

The 3 nd 2 nd planetary gears 34b are arranged at equal intervals in the circumferential direction of the central axes J1, J2. The 3 nd 2 nd planetary gears 34b are meshed with the 2 nd sun gear 31 c. The 3 nd 2 nd planetary gears 34b revolve in the circumferential direction of the respective center axes J1, J2 in accordance with the rotation of the 2 nd sun gear 31 c.

The 2 nd carrier 32 has a 2 nd disc portion 32b, 32 nd counter shafts 32a, and a 3 rd sun gear 32 c. The 2 nd disc part 32b extends in the radial direction around the center axes J1, J2. The 32 nd auxiliary shafts 32a extend from the 2 nd disc portion 32b to one axial side. The 3 rd sun gear 32c extends from the 2 nd disc portion 32b to the other axial side about the central axes J1, J2.

The 2 nd planetary gears 34b are rotatably supported by the 32 nd counter shafts 32 a. The 2 nd carrier 32 rotates about the central axes J1, J2 in accordance with the revolution of the 3 nd planetary gears 34 b.

The 3 rd sun gear 32c is a part of the 2 nd carrier 32, and therefore rotates about the central axes J1, J2 in accordance with the revolution of the 2 nd planetary gear 34 b.

The 3 rd 3 planetary gears 35b are arranged at equal intervals in the circumferential direction of the central axes J1, J2. The 3 rd 3 planetary gears 35b are meshed with the 3 rd sun gear 32 c. The 3 rd 3 planetary gears 35b revolve in the circumferential direction of the central axes J1, J2 as the 3 rd sun gear 32c rotates.

The 3 rd carrier 36 has a 3 rd disc portion 36b, 3 rd counter shafts 36a, and an output portion 36 c. The 3 rd disc portion 36b extends in the radial direction around the center axes J1, J2. The 3 rd auxiliary shafts 36a extend from the 3 rd disc portion 36b to one axial side. The output portion 36c extends from the 3 rd disc portion 36b to the other axial side about the central axes J1, J2.

The 3 rd 3 counter shafts 36a rotatably support the 3 rd planetary gear 35b, respectively. The 3 rd counter shaft 36a rotates about the central axes J1, J2 as the 3 rd planetary gear 35b revolves.

The output portion 36c includes a columnar portion 36f extending around the central axes J1 and J2, and a fitting shaft portion (protrusion) 37 extending in the axial direction from the distal end surface of the columnar portion 36 f. The cylindrical portion 36f is rotatably supported by a bearing portion 39d of the gear housing 39. In addition, a holding hole 36d is provided in an end surface of the output portion 36c facing the other side (the (-Z side) in the axial direction. A shaft 36p is inserted into the holding hole 36 d.

The 1 st and 2 nd pinion gears 5A and 5B are disposed centering on the central axes J1 and J2, respectively. The 1 st and 2 nd pinion gears 5A and 5B are provided with through holes 5h penetrating in the axial direction. A shaft 36p is inserted into the through hole 5 h.

The shaft 36p extends around the central axes J1 and J2. One axial end of the shaft 36p is supported by the output portion 36c, and the other axial end is supported by the metal fitting 40 via the bearing 6. The shaft 36p assists rotation of the 1 st and 2 nd pinion gears 5A, 5B about the respective center axes J1, J2.

Fitting recesses 38 are provided on the surfaces of the 1 st and 2 nd pinion gears 5A and 5B facing one axial side (+ Z side). The fitting shaft portion 37 is inserted into the fitting recess portion 38. Thereby, the 1 st motor main body 20A rotates the 1 st pinion gear 5A via the 1 st planetary gear mechanism 30A. Similarly, the 2 nd motor main body 20B rotates the 2 nd pinion gear 5B via the 2 nd planetary gear mechanism 30B.

As shown in fig. 1, the rack gear 3 has a plate shape whose vertical direction is the plate thickness direction. The rack gear 3 is molded by MIM (Metal Injection Molding).

The 1 st and 2 nd pinion gears 5A and 5B are disposed adjacent to each other in a direction perpendicular to the central axes J1 and J2 (in the X-axis direction in the present embodiment). The rack gear 3 linearly extends along a direction (X-axis direction) in which the 1 st and 2 nd pinion gears 5A and 5B are arranged.

The rack gear 3 is located on the lower side with respect to the 1 st and 2 nd pinion gears 5A, 5B. The rack gear 3 is provided with a tooth surface 3k on the upper surface 3a side. The 1 st and 2 nd pinion gears 5A and 5B are vertically meshed to face the rack gear 3.

The rack gear 3 meshes with the 1 st pinion 5A and the 2 nd pinion 5B. The rack gear 3 is moved in the X-axis direction by being transmitted with power output from the 1 st and 2 nd pinion gears 5A, 5B.

In the following description, the direction in which the rack gear 3 is driven is referred to as a driving direction. That is, the rack gear 3 extends in the driving direction. In the present embodiment, the driving direction coincides with the X-axis direction. The Z-axis direction may be referred to as a width direction of the rack gear 3.

According to the driving device 1 of the present embodiment, the 1 st and 2 nd gear motors 2A and 2B drive the 1 st rack gear 3 to be driven. Therefore, the drive device 1 can drive the rack gear 3 with high output. Further, the rotation of the 1 st and 2 nd gear motors 2A, 2B can be converted into parallel motion.

According to the driving device 1 of the present embodiment, the 1 st and 2 nd gear motors 2A and 2B have a cylindrical shape arranged in line along the X-axis direction. Therefore, the dimension of the driving device 1 in the height direction (Y-axis direction) can be suppressed, and the driving device 1 can be easily mounted on an electronic apparatus that is thin in the Y-axis direction. That is, according to the present embodiment, by using the 1 st and 2 nd motor main bodies 20A and 20B, the dimension in the Y axis direction can be suppressed while ensuring the output of the drive device 1. Further, compared to the case where the stators are stacked in the axial direction, it is not necessary to make the rotor magnet long in the axial direction, and damage to the rotor magnet can be suppressed even when an impact or the like is applied.

The rack gear 3 has an upper surface 3a facing the upper side and a lower surface 3b facing the lower side. The tooth surfaces 3k provided on the upper surface 3a side are aligned along the driving direction of the rack gear 3.

The upper surface 3a of the rack gear is provided with opposed surfaces 3f disposed on both sides of the tooth surface 3k in the width direction. The facing surface 3f is an upward surface. That is, the frame 10 has a pair of opposing surfaces 3f disposed on both sides of the tooth surface 3k in the width direction. The opposed face 3f extends along the driving direction of the rack gear 3.

A groove 3g extending in the driving direction is provided on the opposing surface 3 f. In the present embodiment, 1 recessed groove 3g is provided in each of the pair of opposing surfaces 3 f. The grooves 3g are open on the upper side. The groove 3g is located at the widthwise center of the opposed surface 3 f. The grooves 3g extend uniformly over the entire area of the opposed face 3f in the driving direction.

As described above, the rack and pinion 3 of the present embodiment is a molded article formed by MIM. Therefore, the rack and pinion 3 has a trace 3t of the knock pin left therein during molding.

In the present embodiment, the trace 3t of the knock pin is provided on the facing surface 3 f. In the present embodiment, the trace 3t of the knock pin is provided in the concave groove 3 g. The traces 3t are formed in a concave shape on the bottom surface of the groove 3 g. The traces 3t are formed in a stripe shape on the side surfaces of the recessed groove 3 g. The plurality of traces 3t are arranged at equal intervals along the driving direction of the rack gear 3. By disposing the knock pin above the tooth surface 3k of the rack gear 3, the rack gear 3 can be smoothly separated from the mold.

Recessed step portions 4 are provided at both widthwise edge portions of the lower surface 3 b. The step 4 extends along the driving direction. The step portion 4 has a 1 st step surface 4a facing downward and a 2 nd step surface 4b facing outward in the width direction of the rack gear 3. The 1 st step surface 4a is located above the lower surface 3b of the rack and pinion 3. The 1 st step faces 4a of the rack and pinion 3 on the one side and the other side in the width direction are located on the same plane as each other.

Fig. 3 is an exploded view of the drive device 1.

The frame 10 supports the 1 st gear motor 2A and the 2 nd gear motor 2B. A fitting 40 is fixed to the frame 10. The frame 10 slidably supports the rack gear 3.

The frame 10 includes a plurality of (2 in the present embodiment) outer shell portions 11, a support frame portion 12, and a plurality of fixing portions 15. The frame 10 is formed by MIM.

The 2 casing parts 11 support the 1 st and 2 nd gear motors 2A, 2B, respectively. The housing portion 11 is open on the upper side. The case 11 accommodates and fixes the 1 st or 2 nd gear motors 2A and 2B in the opening. In the present embodiment, 2 housing portions 11 are arranged in the X-axis direction.

The fixing portion 15 has a plate shape along a plane (XZ plane) perpendicular to the vertical direction. The fixing portion 15 is provided with a fixing hole 15a penetrating in the plate thickness direction. Screws for fixing the drive device 1 to an external member (for example, a case of an electronic device housing the drive device 1) are inserted into the fixing holes 15 a. The frame 10 is fixed to the exterior member at the fixing portion 15.

The support frame 12 is disposed on the other axial side (on the Z side) of the 2 casing portions 11. The support frame 12 has a frame shape surrounding the 1 st and 2 nd pinion gears 5A and 5B from four sides. A rectangular enclosure space enclosed by the support frame 12 in a plan view is open in the vertical direction. The support frame 12 has an upper opening and a lower opening with the vertical direction being the opening direction. The lower opening is covered with a rack gear 3. In addition, a fitting 40 is inserted into the upper opening.

As shown in fig. 3, the fitting 40 is inserted into the support frame 12 and fixed to the support frame 12. Thus, the fitting 40 reinforces the frame 10 around the 1 st and 2 nd pinion gears 5A, 5B. The fitting 40 holds the bearing 6. That is, the metal fitting 40 rotatably supports the shaft 36p via the bearing 6. The fitting 40 of the present embodiment is formed by MIM.

The support frame 12 includes: a 1 st surrounding wall (guide wall) 13a located on one side (+ Z side) in the axial direction of the 1 st and 2 nd pinion gears 5A, 5B; a 2 nd surrounding wall (guide wall) 13b located on the other side in the axial direction (the (-Z side); a 3 rd surrounding wall (connecting wall portion) 13c located on the driving direction side (-X side) of the rack and pinion 3; and a 4 th surrounding wall (connecting wall portion) 13d located on the other side (+ X side) of the driving direction of the rack gear 3. That is, the frame 10 has the 1 st to 4 th surrounding walls 13a to 13d arranged in a rectangular shape when viewed from the vertical direction.

The 1 st surrounding wall 13a and the 2 nd surrounding wall 13b extend along the driving direction of the rack gear 3. The 1 st surrounding wall 13a and the 2 nd surrounding wall 13b are opposed to each other in the width direction of the rack gear 3. A pair of notches 16 opened on the upper side are provided in the 1 st surrounding wall 13 a. The bearings 39d of the 1 st and 2 nd gear motors 2A and 2B are inserted into the pair of notches 16, respectively.

Fig. 4 is a perspective view of the frame 10 viewed obliquely from below.

The 1 st surrounding wall 13a and the 2 nd surrounding wall 13b are located on both sides in the width direction of the rack gear 3. That is, the rack gear 3 is sandwiched by the 1 st surrounding wall 13a and the 2 nd surrounding wall 13b from both sides in the width direction.

The 1 st surrounding wall 13a and the 2 nd surrounding wall 13b have rack guide portions 14 protruding from lower end portions thereof respectively inward in the width direction of the rack gear 3. That is, the frame 10 has a pair of rack guides 14. The rack guide 14 extends along the driving direction of the rack gear 3. The pair of rack guides 14 covers a part of the 1 st step surface 4a of the respectively different step portions 4 of the rack gear 3.

The rack guide portion 14 has a 2 nd guide surface 14b located at the front end in the projecting direction. The 2 nd guide surface 14b is a flat surface extending along the driving direction of the rack and pinion 3. The 2 nd guide surfaces 14b of the pair of rack guide portions 14 face each other in the width direction of the rack gear 3.

The pair of rack guide portions 14 are located at the lower opening of the support frame 12. The pair of rack guide portions 14 protrude in directions opposite to each other, respectively. In addition, the pair of rack guide portions 14 extend in parallel with a uniform cross section along the direction (X-axis direction) in which the rack gear 3 extends.

Fig. 5 and 6 are sectional views of the driving device 1 including the step portion 4 of the rack gear 3. Fig. 5 is a sectional view of the drive device 1 along the 1 st center axis J1, and fig. 6 is a sectional view of the drive device 1 along the driving direction.

As shown in fig. 6, the rack guide 14 is located on the lower side with respect to the rack gear 3. The rack guide 14 has a plurality of (2 in the present embodiment) slide bases 14 a. The plurality of slide bases 14a are arranged along the driving direction of the rack gear 3. The slide base 14a protrudes upward.

The slide base 14a is provided at its upper end with a slide surface 14f facing upward. The sliding surfaces 14f of the plurality of slide bases 14a are arranged on the same plane. The sliding surface 14f is in contact with the 1 st step surface 4a of the rack and pinion 3 in the vertical direction so as to face each other. The rack guide portion 14 supports the rack gear 3 from below at the sliding surface 14f so that the rack gear 3 can slide. Thereby, the support frame 12 guides the movement of the rack gear 3 in the X-axis direction.

The rack gear 3 receives a downward force from the 1 st and 2 nd pinion gears 5A, 5B by power transmission from the 1 st and 2 nd pinion gears 5A, 5B to the rack gear 3. According to the present embodiment, the rack guide portion 14 supports the 1 st stepped surface 4a of the rack gear 3 on the sliding surface 14f of the slide base 14 a. This can limit the area of the sliding portion between the rack gear 3 and the rack guide portion 14, thereby reducing frictional resistance. Further, by limiting the area of the sliding surface 14f, the region in which the dimensional management and the surface roughness management are performed can be limited. Therefore, additional processing such as cutting can be performed to improve the dimensional accuracy of the sliding surface 14f and to improve the surface properties, thereby reducing the frictional resistance between the rack gear 3 and the rack guide portion 14.

In the present embodiment, some of the plurality of sliding surfaces 14f are located directly below the 1 st central axis J1. Similarly, some of the sliding surfaces 14f are located directly below the 2 nd central axis J2. The sliding surface 14f receives a force transmitted from the 1 st and 2 nd pinion gears 5A and 5B to the lower side of the rack gear 3. The sliding surface 14f is disposed directly below the 1 st and 2 nd central axes J1, J2, and thus the deflection of the rack and pinion 3 can be suppressed, and the sliding efficiency of the rack and pinion 3 can be improved.

As shown in fig. 5, the 2 nd guide surface 14b of the rack guide portion 14 guides the 2 nd stepped surface 4b in the width direction of the rack gear 3 so as to face the 2 nd stepped surface 4b of the rack gear 3. The rack guide 14 restricts the movement of the rack gear 3 in the width direction. Thereby, the rack guide 14 can efficiently move the rack gear 3 in parallel.

As shown in fig. 4, the 3 rd surrounding wall 13c and the 4 th surrounding wall 13d extend in the width direction of the rack gear 3. The 3 rd surrounding wall 13c and the 4 th surrounding wall 13d are opposed to each other in the driving direction of the rack gear 3. That is, the 3 rd surrounding wall 13c and the 4 th surrounding wall 13d are aligned in the driving direction. The 3 rd surrounding wall 13c and the 4 th surrounding wall 13d are located at an upper side of the rack gear 3. The 3 rd and 4 th surrounding walls 13c and 13d connect the 1 st and 2 nd surrounding walls 13a and 13b to each other. This increases the rigidity of the 1 st to 4 th enclosing walls 13a to 13 d.

A pair of 1 st guide surfaces (guide surfaces) 13f that guide the rack and pinion 3 from above are provided on the lower surfaces of the 3 rd surrounding wall 13c and the 4 th surrounding wall 13d, respectively. The pair of 1 st guide surfaces 13f are aligned with each other in the width direction of the rack and pinion 3. The 1 st guide surface 13f is a flat surface.

As shown in fig. 6, the 1 st guide surface 13f is located directly above the facing surface 3f of the rack and pinion 3. The 3 rd surrounding wall 13c and the 4 th surrounding wall 13d guide the action of the rack gear 3 from the upper side. That is, the 1 st guide surface 13f of the 3 rd surrounding wall 13c and the 4 th surrounding wall 13d guides the operation of the rack gear 3 from above. Further, when the rack gear 3 receives a downward force from the 1 st and 2 nd pinion gears 5A and 5B by transmitting power from the 1 st and 2 nd pinion gears 5A and 5B, a slight gap is generated between the 1 st guide surface 13f and the opposed surface 3 f. Further, when the rack gear 3 receives a force from a driving target, the 1 st guide surface 13f and the facing surface 3f slide with each other.

As described above, the opposed surface 3f of the present embodiment is provided with the concave groove 3 g. The rack gear 3 of the present embodiment is provided with a pair of opposing faces 3f, and the pair of opposing faces 3f is provided with 1 groove 3 g. Therefore, the contact portions of the rack gear 3 and the 1 st guide face 13f extend in a stripe shape of 4 stripes in total in the driving direction.

In the case where the recessed groove 3g is not provided in the facing surface 3f, the reduction in the molding accuracy of the facing surface 3f in the width direction of the rack and pinion 3 easily leads to an increase in the frictional resistance between the 1 st guide surface 13f and the facing surface 3 f. According to the present embodiment, the facing surface 3f is provided with the concave groove 3g extending in the driving direction of the rack and pinion 3, so that the width-direction dimension of the facing surface 3f can be reduced. Therefore, even when the molding accuracy of the rack gear 3 is low, the frictional resistance can be reduced by limiting the contact area between the 1 st guide surface 13f and the facing surface 3 f. Therefore, the sliding efficiency can be improved without polishing the facing surface 3f or the like, and the drive device 1 can be manufactured at low cost.

In the present embodiment, the surface provided with the concave groove 3g is the facing surface 3f facing upward. However, the above-described effect can be obtained even if the face provided with the grooves 3g is a face facing downward. That is, the surface provided with the recessed groove 3g is a surface facing the 1 st guide surface 13f in the present embodiment, but may be a surface facing a surface (the 1 st guide surface 13f in the present embodiment) that guides the rack gear from one side in the vertical direction and restricts the rack gear from moving to one side in the vertical direction. Therefore, the recess 3g may be provided on the 1 st step surface 4a, for example.

According to the present embodiment, the recess 3g is provided with the trace 3t of the knock pin. The knock pin is provided on the tooth surface 3k side, whereby the tooth surface 3k is smoothly released from the mold. Therefore, the trace 3t of the knock pin is preferably disposed on the side of the surface (upper surface) of the rack gear 3 on which the tooth surface 3k is provided, and is difficult to be disposed in a portion other than the facing surface 3f within the range of the dimension in the width direction. The trace 3t of the knock pin is formed slightly recessed with respect to its periphery. If the trace 3t of the knock pin is disposed on the opposed surface 3f, there is a possibility that a step derived from the trace 3t becomes resistance at the time of sliding. According to the present embodiment, the traces 3t are disposed in the recessed grooves 3g, so that the traces 3t are not exposed on the facing surface 3 f. This allows the rack and pinion 3 to be smoothly molded by the knock pin, and prevents the trace 3t of the knock pin from becoming resistance during sliding.

According to the present embodiment, the opposed surfaces 3f are disposed on both sides of the tooth surface 3k in the width direction, and the concave grooves 3g are provided on the opposed surfaces 3 f. Therefore, the rack gear 3 can be stably slid with respect to the frame 10 on both sides of the tooth surface 3k in the width direction. Further, when the trace 3t of the knock pin is disposed in the concave groove 3g, the rack and pinion 3 can be smoothly separated from the mold.

According to the present embodiment, the concave groove 3g extends over the entire movable region of the rack and pinion 3. Therefore, the edge of the recessed groove 3g can be suppressed from becoming resistance when sliding with the 1 st guide surface 13 f. Here, the entire movable region of the rack gear 3 refers to the entire region in the sliding direction in which the 1 st guide surface 13f is slidable with respect to the facing surface 3 f.

According to the present embodiment, the frame 10 supports the rack gear 3 from below by the sliding surface 14f and is guided from above by the 1 st guide surface 13 f. Therefore, the rack gear 3 can be suppressed from being disengaged from the frame 10. In particular, in the present embodiment, the sliding surface 14f and the 1 st guide surface 13f are provided in 1 member (frame 10). Therefore, the relative dimensional accuracy of the sliding surface 14f and the 1 st guide surface 13f can be easily improved, and the sliding efficiency of the rack and pinion 3 can be improved.

(modification 1)

Fig. 7 is a perspective view of a rack gear 103 of modification 1 that can be adopted as the rack gear of the above embodiment. The rack gear 103 of the present modification is different from the above-described embodiment in that a stepped portion 103g is provided instead of the recessed groove 3 g.

The same reference numerals are given to the same constituent elements as those of the above embodiment, and the description thereof will be omitted.

As in the above-described embodiment, the facing surface 103f of the rack gear 103 faces the 1 st guide surface 13f (see fig. 6 and the like) and extends in the driving direction. In the present modification, recessed step portions 103g are provided on the facing surface 103f, which are located at both widthwise edges of the rack and pinion 103 and extend in the driving direction. Thus, as in the above-described embodiment, the width-directional dimension of the facing surface 103f can be reduced, and the sliding efficiency can be improved even when the flatness of the rack and pinion 103 is low. Further, as in the above-described embodiment, by providing the stepped portion 103g with the trace 103t of the knock pin, the trace 103t of the knock pin can be suppressed from becoming resistance at the time of sliding.

(modification 2)

Fig. 8 is a perspective view of a rack gear 203 of modification 2 that can be adopted as the rack gear of the above embodiment. The rack and pinion 203 of the present modification is different from the above-described embodiment mainly in that a plurality of concave grooves 3g are provided.

The same reference numerals are given to the same constituent elements as those of the above embodiment, and the description thereof will be omitted.

As in the above-described embodiment, the facing surface 203f of the rack gear 203 faces the 1 st guide surface 13f (see fig. 6 and the like) and extends in the driving direction. In the facing surface 203f of the present modification, a plurality of concave grooves 203g are arranged discretely along the driving direction of the rack gear 203. In this modification as well, since the contact area between the facing surface 203f and the 1 st guide surface 13f can be limited, a certain effect of improving the driving efficiency of the rack gear 203 can be obtained. Further, as in the above-described embodiment, by providing the trace 203t of the knock pin in at least a part of the plurality of concave grooves 203g, it is possible to suppress the trace 203t of the knock pin from becoming resistance at the time of sliding.

In the present modification, a case where a plurality of concave grooves 203g are provided is described. However, the stepped portions 103g described as the modification 1 may be arranged discretely along the driving direction of the rack and pinion.

While the embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The present invention is not limited to the embodiments.

Claims (6)

1. A drive device, comprising:

a rack gear extending in the driving direction and provided with a tooth surface on an upper surface side;

a gear motor having a motor main body, a transmission mechanism connected to the motor main body, and a pinion gear engaged with the rack gear, the pinion gear being connected to the transmission mechanism and rotating around a central axis; and

a frame that slidably supports the rack gear,

the frame has a guide surface that guides the rack gear from one side in the vertical direction and restricts the rack gear from moving to one side in the vertical direction,

the rack gear has an opposed surface opposed to the guide surface and extending in the driving direction,

the facing surface is provided with a groove extending in the driving direction or recessed steps located at both edges in the width direction and extending in the driving direction.

2. The drive apparatus according to claim 1,

the rack gear is a molded product and is provided with a gear rack,

the opposite face is a face facing the upper side,

and the trace of the ejector pin is arranged on the groove or the step part.

3. The drive device according to claim 2,

the opposed surfaces are respectively arranged on both sides in the width direction of the tooth surface,

the groove or the step portion is provided on each of the opposed faces.

4. The drive device according to any one of claims 1 to 3,

the recessed groove or the stepped portion extends over the entire area where the guide surface is slidable with respect to the opposite surface.

5. The drive device according to any one of claims 1 to 3,

the grooves or the stepped portions are arranged in plurality discretely along the driving direction.

6. The drive device according to any one of claims 1 to 3,

the drive device has a plurality of the gear motors, and the pinion gear of each of the gear motors is engaged with the rack gear.

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