JPH0662254U - Linear drive mechanism - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention relates to a linear drive mechanism, which can achieve stable miniaturization and cost reduction, as well as stable and smooth drive at high speed drive, and prevent vibration from occurring. It is also an object of the present invention to provide a linear drive mechanism capable of reliably preventing the situation where the drive is stopped by protecting the guide portion of the passive rack from dust and the like. . [Structure] A passive rack 11 is integrally formed with guide rails 15a and 15b, and the guide rails 15a and 15b are supported on the case 14 via roller bearings 16 rotatably provided on the case 14. There is.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a linear drive mechanism that converts a rotary motion into a linear motion, and more particularly, to a linear drive mechanism that can stably guide a passive rack linearly at high speed.

[0002]

[Prior art]

 In general, machine tool feeders are equipped with a linear drive mechanism that converts rotational motion into linear motion.Recently, instead of a rack and pinion mechanism or a pin rack mechanism, a passive rack having cycloidal teeth is used. Further, a linear drive mechanism has been developed which is composed of an active rack which meshes with the passive rack while maintaining a predetermined phase difference, and which can perform highly rigid and highly accurate positioning.

This linear drive mechanism is usually called L-EMA (Linear-Electro-Mechanical-Actuator), and has a passive rack having a plurality of teeth and a plurality of teeth that mesh with the teeth of the passive rack. A plurality of active racks formed with are separated from each other in parallel with each other, and the plurality of active racks are held with a predetermined phase difference to be engaged with the passive rack, and the plurality of active racks are rocked by the phase difference. It is provided with one or more crank shafts that perform a crank motion, and a support member that rotatably supports the crank shafts.

In this linear drive mechanism, when the crank shaft is driven by the drive motor, the plurality of active racks perform the swing crank motion while maintaining a predetermined phase difference. One always contacts the teeth of the passive rack, and the swinging of the active rack causes the passive rack to move linearly. By the way, when the passive rack linearly moves, a linear guide for guiding the passive rack is required in order to smoothly move the passive rack. As a conventional linear guide of this type, for example, FIG. The ones shown in (a) and (b) are known.

This device is composed of a rail 1 coupled to a passive rack and a bearing 2 slidably provided on the rail 1. The bearing 2 has a circulating ball 3 inside, and the circulating ball 3 is circulated in a circulating hole 4 formed in the bearing 2 in an annular shape. In the linear guide having such a configuration, when the passive rack moves linearly, the bearing 2 moves along the rail 1 along with the passive rack. At this time, the lower end side of the circulation ball 3 slidably contacts the rail 1 and circulates in the circulation hole 4, so that the bearing 2 slides smoothly along the rail 1. 4 (a) and 4 (b), 6 is an end cap for closing the end of the bearing 2, and 7 (b) is provided at the end of the circulation hole 4, and the moving end of the circulating ball 3 is provided. It is a return guide that guides the unit side in a U shape.

[0006]

[Problems to be solved by the device]

 However, in such a conventional linear drive mechanism, since the circulating ball 3 circulates in the circulating hole 4, the circulating ball 3 smoothly circulates when the passive rack moves at high speed. Therefore, there was a problem that the passive rack could not be driven stably at high speed.

Further, since the circulating ball 3 is configured to be in sliding contact with the rail 1, the circulating ball 3 is in a non-loaded region (indicated by an arrow b) in which the circulating ball 3 slides in contact with the rail 1 from a high load region (indicated by an arrow a). There is a problem that noise is generated with a large vibration when it rapidly changes to (). Especially, in the high-speed drive range, the kinetic energy of the passive rack becomes large, and the noise also becomes louder as the speed increases.

Furthermore, since the circulation hole 4 for accommodating the circulation ball 3 is provided, cutting chips, dust, dust, etc. of the workpiece enter the circulation hole 4, and the dust etc. If it sticks, the linear guide cannot be used and the linear drive mechanism may not operate. Therefore, according to the first aspect of the present invention, a linear guide rail is integrally formed on the passive rack, and the linear guide rail is supported by the support member via a bearing rotatably provided on the support member. While achieving downsizing and cost reduction, it is possible to drive stably and smoothly during high-speed driving, prevent vibrations from occurring, and protect the guide part of the passive rack from dust, etc. It is an object of the present invention to provide a linear drive mechanism that can reliably prevent a situation in which the drive is stopped by being protected.

According to the second aspect of the invention, the linear guide rail can be supported with high rigidity by configuring the bearing with a plurality of roller bearings arranged in the extending direction of the passive rack. The purpose of the present invention is to provide a linear drive mechanism that can drive more stably and smoothly during high-speed driving. According to the third aspect of the present invention, by constructing the bearing from an angular contact type bearing, it is possible to reduce the load applied to the passive rack during high-speed driving, and at the same time, to reduce the cost. The purpose is to provide a drive mechanism.

[0010]

[Means for Solving the Problems]

 To achieve the above object, a device according to claim 1 has a plurality of teeth, a passive rack having a plurality of teeth, a plurality of active racks having a plurality of teeth that mesh with the teeth of the passive rack, and a plurality of active racks spaced from each other in parallel with each other. The active rack is held with a predetermined phase difference to be meshed with the passive rack, and at least one crankshaft and the crankshaft are rotated by the swinging crank motion of the plurality of active racks by the phase difference. In the linear drive mechanism, which includes a support member that freely supports, and linearly moves the receiving rack through a plurality of active racks by swinging the crankshaft, the length of the passive rack is increased. Linear guide rails are integrally formed at both ends in the direction of the passive rack in the longitudinal direction, and the linear guide rails are supported on the support member via bearings rotatably provided on the support member. By lifting, it is characterized by guiding the passive rack through the linear guide rail.

To achieve the above object, the invention according to claim 2 is the device according to claim 1, wherein the bearing is composed of a plurality of roller bearings arranged in a direction in which the passive rack extends. It is characterized by that. To achieve the above object, the invention according to claim 3 is characterized in that, in the invention according to claim 1, the bearing is composed of an angular contact type bearing.

[0012]

[Action]

 According to the first aspect of the present invention, the passive rack is formed integrally with the linear guide rail, and the linear guide rail is supported by the supporting member via the bearing rotatably provided on the supporting member. Therefore, by integrating the passive rack and the guide rail, the linear drive mechanism can be stably and smoothly driven at high speed drive while achieving downsizing and cost reduction. Moreover, since the load applied to the bearing does not change abruptly, vibration does not occur. Furthermore, there may be a situation in which dust or the like does not adhere between the guide portion of the passive rack, that is, between the guide rail and the bearing, the guide portion is protected from dust and the linear drive mechanism is stopped. There is no.

According to the second aspect of the invention, the bearing is composed of a plurality of roller bearings arranged in the extending direction of the passive rack. Therefore, the linear guide rail is supported by the supporting member with high rigidity, and is more stably and smoothly driven at high speed driving. According to the third aspect of the invention, the bearing comprises an angular contact type bearing. Therefore, the load applied to the passive rack during high-speed driving can be reduced and the cost of the linear drive mechanism can be reduced.

[0014]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings. 1 and 2 are views showing an embodiment of a linear drive mechanism according to the invention of claims 1 and 2. First, the configuration will be described. In FIGS. 1 and 2, 11 is a passive rack having a plurality of teeth T1 and 12A, 12B and 12C are a plurality of teeth (T2) having the same pitch as the pitch of the teeth T1 of the passive rack 11. In the embodiment, there are three) active racks. The tooth T1 of the passive rack 11 is formed in, for example, a trochoidal curve or cycloidal curve (waveform) tooth profile, and the tooth T2 of the active racks 12A to 12C has a radius approximately the same as the circle serving as the reference of this tooth profile. Is formed to have a tooth profile.

As is well known, the active racks 12A to 12C are provided with a crankshaft 13A (note that the portion indicated by 13B in FIG. 1 is also provided with a crankshaft having the same structure as the crankshaft 13A, but the illustration thereof is omitted. ) Is supported via an eccentric cam (not shown) fixed to each other, and each tooth T2 faces the passive rack 11 in this state. Then, the crankshaft 13 and the other crankshafts are supported by the case 14 as a supporting member, so that the teeth T2 of the active racks 12A to 12C mesh with the passive rack 11. Further, the crankshaft 13A has an eccentric cam (not shown), which is formed at equal angular intervals (120 ° intervals in this embodiment), and when the crankshaft 13A and other crankshafts rotate, The plurality of active racks 12A to 12C perform swinging crank movements while maintaining a predetermined phase difference (120 ° in this embodiment).

An input shaft is integrally formed with the crankshaft 13A, and an output shaft of a drive motor (not shown) is connected to the input shaft. When one crankshaft 13A is driven by the drive motor via the input shaft, the plurality of active racks 12A to 12C are eccentrically oscillated by the rotation of the crankshaft 13A and the other crankshafts are interlockedly rotated. It is like this.

On the other hand, linear guide rails 15a and 15b are integrally formed on the passive rack 11 along the longitudinal direction of the passive rack 11, and the guide rails 15a and 15b are provided with a plurality of roller bearings 16 therebetween. Supported by case 14. The roller bearings 16 are rotatably supported in the case 14, and a plurality of roller bearings 16 are arranged in the extending direction of the passive rack 11 so that both ends of the guide rails 15a and 15b are vertically sandwiched. 14 is provided (note that in FIG. 1, only a part of the case 14 is shown so that the swing racks 12A to 12C can be seen from the outside, but the case 14 stores the whole swing racks 12A to 12C. is doing).

Next, the operation will be described. When one crankshaft 13A is driven by the drive motor via the input shaft, the plurality of active racks 12A to 12C perform a swinging crank motion while maintaining a predetermined phase difference, and simultaneously rotate the other crankshafts. At this time, the reaction racks 12A to 12C eccentrically swing, and the passive rack 11 whose one side surface of T1 is pushed by the tooth T2 moves in the longitudinal direction. Further, since the active racks 12A to 12C perform the swinging crank motion while maintaining the phase difference according to the number of racks, the plurality of swinging racks 12A to 12C are rotated during one revolution of the crankshaft 13A and other crankshafts. At least one of the teeth T1 comes into contact with the passive rack 11, and the swinging of the active rack pushes the passive rack in the straight direction. At this time, the passive rack 11 is guided in a straight direction while the guide rails 15a and 15b integrally formed at both ends in the longitudinal direction are supported by the case 14 via the roller shaft 16.

As described above, in this embodiment, the passive rack 11 is formed integrally with the guide rails 15a and 15b, and the guide rails 15a and 15b are provided on the case 14 via the roller bearing 16 rotatably provided. Since it is supported by the case 14, it is possible to drive the passive rack 11 stably and smoothly when the passive rack 11 is driven at high speed, while achieving downsizing and cost reduction of the linear drive mechanism. According to the experiment, it was possible to cope with high-speed applications of 0, 3 to 2 and 0 m / sec (18 to 120 m / min), which were not possible in the past.

Further, since the load applied to the roller bearing 16 does not change abruptly, it is possible to prevent vibration from occurring. Further, the passive rack 11 may cause rattling during the rectilinear motion due to the swinging motion of the active racks 12A to 12C, and the rattling may cause the rattling. Since the rails 15a and 15b are supported by the case 14 so as to be sandwiched by the roller bearings 16 from the vertical direction, it is possible to prevent rattling and vibration, and to smoothly move the passive rack 11 straight. Can be moved in any direction.

Furthermore, it is possible to prevent dust and the like from adhering to the guide portion of the passive rack 11, that is, between the guide rails 15a and 15b and the roller bearing 16, and to protect the guide portion from dust and the like. It is possible to prevent a situation in which the linear drive mechanism is stopped. Further, since a plurality of roller bearings 16 are arranged as bearings in the extending direction of the passive rack, the guide rails 15 can be supported by the case 14 with high rigidity, and are more stable during high-speed driving. It can be driven smoothly.

FIG. 3 is a view showing an embodiment of a linear drive mechanism according to the invention of claim 3. In this embodiment, the same components as those in the above embodiment will be designated by the same reference numerals and the description thereof will be omitted. In this embodiment, a plurality of linear guide rails 22a to 22d are integrally provided on both ends of the passive rack 21 in the longitudinal direction along the longitudinal direction of the passive rack 21, and the guide rails 22a to 22d are freely rotatable in the case 14. It is supported by the case 14 via a roller bearing 23 provided on the. The roller bearing 23 is supported by the case 14 so as to be inclined at a predetermined angle with respect to the axis line of the passive rack 21, and sandwiches both ends of the passive rack 21 from the vertical direction. That is, the roller bearing 23 constitutes an angular contact type bearing.

Also in this embodiment, the passive rack 21 can be stably moved in the straight traveling direction, and at the same time, the same application as that of the above embodiment can be supported during high speed driving. In addition to the same effects as the above-mentioned embodiment, since the roller bearing 23 is composed of an angular contact type bearing, it is possible to reduce the load applied to the passive rack 21 during high-speed driving and reduce the cost. Can respond to.

[0024]

[Effect of device]

 According to the invention of claim 1, since the guide rail is supported by the support member via the bearing rotatably provided on the support member, the linear drive is performed at the time of high speed drive while achieving downsizing and cost reduction. The mechanism can be driven stably and smoothly. Further, since the load applied to the bearing does not change suddenly, it is possible to prevent vibration from occurring. Furthermore, since dust or the like does not adhere to the guide portion of the passive rack, that is, between the guide rail and the bearing, the guide portion can be protected from dust and the linear drive mechanism is stopped. Can be prevented.

According to the second aspect of the invention, since the bearing is composed of a plurality of roller bearings arranged in the extending direction of the passive rack, the linear guide rail is used as a supporting member with high rigidity. It can be supported, and the linear drive mechanism can be driven more stably and smoothly during high speed driving. According to the invention of claim 3, since the bearing is composed of the angular contact type bearing, the load applied to the passive rack at the time of high speed driving can be reduced and the cost of the linear motion mechanism can be reduced. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of a linear drive mechanism according to the invention of claims 1 and 2. FIG.

FIG. 2 is a side view seen from the direction A in FIG.

FIG. 3 is a side view of a linear drive mechanism according to a third aspect of the present invention.

FIG. 4A is a perspective view of a guide mechanism provided in a conventional linear drive mechanism, and FIG. 4B is a schematic sectional view thereof.

[Explanation of symbols]

 11, 21 Passive rack 12A-12C Active rack 13 Crankshaft 14 Case (support member) 15a, 15b, 22a-22d Linear guide rail 16, 23 Roller bearing (bearing)

Claims (3)

[Scope of utility model registration request] 1. A passive rack having a plurality of teeth, a plurality of active racks having a plurality of teeth formed to mesh with the teeth of the passive rack, and a plurality of active racks spaced apart from each other in parallel to maintain a predetermined phase difference between the plurality of active racks. And holding at least one crankshaft for swinging crank movement of the plurality of active racks by the phase difference, and a supporting member for rotatably supporting the crankshaft. In a linear drive mechanism in which a passive rack is linearly moved through a plurality of active racks by swinging a crankshaft, both ends of the passive rack in the longitudinal direction are extended in the longitudinal direction of the passive rack. The linear guide rail is integrally formed, and the linear guide rail is supported by the support member via a bearing rotatably provided on the support member, thereby providing a linear guide. Linear drive mechanism, characterized in that to guide the driven rack through Lumpur. 2. The linear drive mechanism according to claim 1, wherein the bearing is composed of a plurality of roller bearings arranged in the extending direction of the passive rack. 3. The linear drive mechanism according to claim 1, wherein the bearing comprises an angular contact type bearing.