JP2003184988A - Linear actuator and bed for care using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a linear actuator and a bed for care using it in which not only an actuator rod can be expanded by a manual operation, but also a manual maneuverability at that time is good. <P>SOLUTION: A driving force transmitting mechanism 32 of a motor 22 of the linear actuator 18 comprises an input gear 54, a first sun gear 56, a second sun gear 58, and a planetary gear 60 or the like. An external input shaft 66 for rotating the second sun gear 58 is ordinarily prevented from rotating by a clutch mechanism 34 and is permitted to rotate upon manual operation by using a release handle 92. Accordingly, a driving force transmitting path to the motor 22 can be interrupted by a manual operation. At this time, the load of the motor 22 can be removed. Thus, the manual maneuverability is good. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator and a care bed using the linear actuator.

[0002]

2. Description of the Related Art Recently, the demand for electric care beds has been increasing against the backdrop of the expansion of welfare. In this type of electric care bed, as an example, the lower end of the backrest is hinged to a horizontal bed frame, and the linear actuator is activated by performing a predetermined operation to set the backrest to a predetermined position. The angle can be raised.

As a prior art of this type of linear actuator, there is a technology disclosed in Japanese Patent Application Laid-Open No. 9-191611. In the linear actuator disclosed in this publication, for example, when a power failure or a failure of an electric system such as a motor or a controller occurs, the drive screw of the feed screw system cannot expand or contract. It is characterized by the addition of a manual operation mechanism.

More specifically, the rotary shaft of the worm wheel is extended toward the side opposite to the output side, and a handle for manual operation can be connected to this extended portion. Thus, in the event of a power failure or failure, the drive rod can be expanded and contracted by directly operating the worm wheel by connecting and operating the handle.

[0005]

However, in the case of the technique disclosed in the above publication, when the worm wheel is rotated by operating the steering wheel, the motor output shaft connected to the worm wheel is also rotated at the same time. Therefore, a large operating force is required. Therefore, not only the work load is increased, but also there is a possibility of lack of promptness in an urgent case.

In consideration of the above facts, the present invention has an object to obtain a linear actuator which is capable of expanding and contracting an actuator rod by a manual operation and has good manual operability at that time, and a nursing bed using the linear actuator. Is.

[0007]

A linear actuator according to the present invention as set forth in claim 1 is a motor unit which is driven and rotated by being actuated, and an output shaft is rotated about an axis to move a movable body in an axial direction. A drive provided between the motor unit and the expansion / contraction mechanism unit for expanding / contracting the actuator rod by the axial movement of the moving body, and decelerating the rotation speed of the motor unit and transmitting it to the expansion / contraction mechanism unit. Connected to the force transmission mechanism and this driving force transmission mechanism, it allows transmission of driving force by the driving force transmission mechanism during normal operation, and shuts off the driving force transmission path between the motor and driving force transmission mechanism during operation. And a manual operation mechanism section that is provided to be connectable to the clutch mechanism section from the outside and that operates the clutch mechanism section by performing a predetermined manual operation, In the linear actuator provided with the clutch mechanism portion, the clutch mechanism portion is arranged coaxially with respect to the output shaft, rotation around the axis line is normally prevented, and rotation around the axis line is prevented during manual operation by the manual operation mechanism portion. An allowable external input shaft is provided, and the driving force transmission mechanism section includes a first sun gear that rotates integrally with the output shaft, a second sun gear that rotates integrally with the external input shaft, and the second sun gear. (1) a planetary gear that meshes with both the sun gear and the second gear; and a planetary gear that is axially supported and coaxially and relatively rotatable with respect to the output shaft. And an input gear that rotates around the output shaft.

The linear actuator according to the present invention described in claim 1 operates as follows.

Normally, when the motor section operates, the input gear of the driving force transmission mechanism section is driven and rotated around the axis of the output shaft of the expansion mechanism section. Since the input gear is provided so as to be rotatable relative to the output shaft, the output shaft does not rotate even if the input gear rotates. When the input gear rotates around the axis of the output shaft,
The rotational force is transmitted to the planetary gear that is axially supported by the input gear.

Here, the planetary gear meshes with both the first sun gear that rotates integrally with the output shaft and the second sun gear that rotates integrally with the external input shaft. Since the relative rotation of the external input shaft forming a part of the portion with respect to the output shaft is blocked, the second sun gear is set in the non-rotating state. Therefore, normally, the planet gear revolves around the first sun gear and the second sun gear while rotating, but the second sun gear does not rotate but only the first sun gear rotates. This causes the output shaft to rotate about its axis. When the output shaft rotates around the axis, the moving body of the expansion / contraction mechanism unit moves in the axial direction, and the axial movement of the moving body expands / contracts the actuator rod.

On the other hand, the manual operation mechanism is connected to the clutch mechanism at the time of power failure or failure of the electric system. And
When a predetermined manual operation is performed using the manual operation mechanism section, the clutch mechanism section operates and rotation of the external input shaft around the axis is allowed. Therefore, when a rotational force is applied to the external input shaft from the outside by using the manual operation mechanism unit, the external input shaft rotates around its axis, and the second sun gear rotates integrally with the external input shaft accordingly. To do. The rotation of the second sun gear causes the planet gear to rotate, and the planet gear rotates on its axis without revolving, whereby the first sun gear meshing with the planet gear rotates together with the second sun gear. As a result, the output shaft rotates about its axis and the actuator rod expands and contracts.

At this time, since the input gear is provided so as to be rotatable relative to the output shaft, the input gear does not rotate even if the first sun gear rotates. That is, at the time of manual operation, the driving force transmission path between the motor unit and the driving force transmission mechanism unit is cut off, and the load for rotating the motor unit is not added to the manual operation force.

As described above, according to the linear actuator of the present invention, not only the actuator rod can be expanded and contracted by manual operation, but also the manual operability at that time is very good.

Further, in the case of the linear actuator according to the present invention, the driving force of the motor section is expanded and contracted by using the planetary gear device such as the first sun gear, the second sun gear, the planetary gear and the input gear configured as described above. Since the configuration is adopted in which the speed is reduced and transmitted to the mechanism portion, it is possible to interrupt (switch) the driving force transmission path without disengaging the gears from each other. Therefore, it is possible to prevent the occurrence of troubles such as damage to the gear teeth due to the mutual switching between the normal operation and the manual operation being performed several times. As a result, there is also an advantage that the durability and reliability of the linear actuator can be improved.

In the linear actuator according to the present invention described in claim 2, in the invention described in claim 1, the number of teeth of the first sun gear and the number of teeth of the second sun gear are set to be different from each other. It is characterized by

According to the second aspect of the present invention, the number of teeth of the first sun gear and the number of teeth of the second sun gear are set to be different from each other. That is, the planetary gear device constitutes a mysterious planetary gear device. Therefore, a large reduction ratio can be obtained.

In the nursing bed according to the third aspect of the present invention, the backrest portion is rotatably connected to the bed body, and the backrest portion is pivoted between a horizontal position and a position raised by a predetermined angle. The linear actuator according to claim 1 or 2 is applied to a nursing bed to be used.

According to the third aspect of the present invention, the backrest is rotatably connected to the bed body, and the backrest is rotated between a horizontal position and a position raised by a predetermined angle. The linear actuator according to claim 1 or 2 is applied to the bed. Therefore, in an emergency such as a sudden change in the condition of the person requiring care due to a power outage or a failure, the tilted backrest can be quickly brought into a horizontal state by manually operating the linear actuator.

In the nursing bed according to the present invention as defined in claim 4, the foot rest is connected to the bed body so as to be bendable from a portion corresponding to the knee as a starting point, and the foot rest is at a predetermined angle from the horizontal position. The linear actuator according to claim 1 or 2 is applied to a care bed that is bent between a bent position and a bent position.

According to the fourth aspect of the present invention, the foot rest is connected to the bed body so as to be bendable from a portion corresponding to the knee as a starting point, and the foot rest is bent at a predetermined angle from the horizontal position. The linear actuator according to claim 1 or 2 is applied to a care bed that is bent between and. Therefore, in an emergency such as a sudden change in the condition of the care-requiring person due to a power failure or failure, the bent footrest can be quickly brought into a horizontal state by manually operating the linear actuator.

In the nursing bed according to the present invention as defined in claim 5, the bed main body is connected to a pedestal supported on the floor so that the bed main body can move up and down, and the bed main body is located between the lowest position and the highest position. The linear actuator according to claim 1 or 2 is applied to a nursing bed that is lifted up and down.

According to the fifth aspect of the present invention, the bed body is movably connected to the pedestal supported on the floor, and the bed body is moved up and down between the most lowered position and the most raised position. Claim 1 or Claim 2 for a nursing bed
The linear actuator described in 1. is applied. Therefore, in the event of an emergency such as a sudden change in the condition of the person requiring care due to a power outage or a failure, for example, by manually operating the linear actuator, the bed body at the highest position can be quickly moved to the lowest position. it can.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A nursing bed 10 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 shows a schematic side view of a nursing bed 10 according to this embodiment. As shown in this figure, the care bed 10 includes a horizontal portion 12A and a horizontal portion 1A.
The bed frame 12 is composed of legs 12B provided on the front and rear of the back surface of 2A, respectively. The care bed 10 also includes a backrest plate 16 rotatably connected to the bed frame 12 by a hinge 14. The bed frame 12 corresponds to the "bed body" of the present invention, and the backrest plate 16 corresponds to the "backrest portion" of the present invention.

The horizontal portion 12 of the bed frame 12 described above.
A linear actuator 18 is arranged below A. As shown in FIGS. 2 to 5, the linear actuator 18 includes a casing 20 that constitutes an outer shell of the device, a motor portion 22 that is housed in the casing 20 and is driven and rotated by operating the “output shaft”. By rotating the screw shaft 24 as an axis about the axis, the nut 26 as a "moving body" is moved in the axial direction, and the actuator rod 28 is expanded and contracted by the axial movement of the nut 26, and the motor section 22. And the motor unit 2 provided between the expansion and contraction mechanism unit 30.
The driving force transmission mechanism unit 32 that reduces the rotation speed of the second rotation unit 2 and then transmits it to the expansion and contraction mechanism unit 30, and the driving force transmission mechanism unit 32.
And a clutch mechanism section 34 for allowing the transmission of the driving force by the driving force transmission mechanism section 32 during normal operation and for disconnecting the driving force transmission path between the motor section 22 and the driving force transmission mechanism section 32 during operation, and this clutch. A manual operation mechanism portion 36, which is provided to the mechanism portion 34 so as to be connectable from the outside and operates the clutch mechanism portion 34 by performing a predetermined manual operation, is configured as a main component. Hereinafter, the configuration of each unit will be described in this order.

As shown in FIGS. 2 and 3, the casing 20 is composed of a main body 20A having a substantially rectangular parallelepiped shape and a pipe holder 20B fixed to the main body 20A and having a substantially cylindrical shape. Has been done. further,
Inside the main body portion 20A of the casing 20, a resin plate 38 for partitioning the internal space and mounting components is arranged. The resin plate 38 includes a motor mounting portion 38A formed in a substantially flat plate shape, a substantially cylindrical expansion-contraction mechanism mounting portion 38B provided on one surface of the motor mounting portion 38A, and a motor mounting portion. A driving force transmission mechanism housing portion 38C provided on the surface opposite to the portion 38A, and a clutch mechanism formed coaxially with the driving force transmission mechanism housing portion 38C and projecting from the main body portion 20A of the casing 20 to the outside. And a housing portion 38D.

The motor portion 22 is disposed on the motor mounting portion 38A of the resin plate 38 described above. The motor unit 22 is operated to rotate the output shaft 40A about its axis, a motor main body 40, a pinion gear 42 fixed to the outer peripheral portion of the output shaft 40A, and arranged adjacent to the pinion gear 42. And a reduction gear 44 having a large diameter.

Further, the expansion / contraction mechanism portion 30 is disposed on the expansion / contraction mechanism mounting portion 38B of the resin plate 38. More specifically, the base end portion of the pipe holder 20B of the casing 20 having a cylindrical shape is attached to the expansion mechanism attachment portion 38B. A screw shaft 24 is arranged at the axial center of the pipe holder 20B. The outer peripheral surface of the base end portion of the screw shaft 24 is a smooth surface, and this portion is supported by the shaft center portion of the guide member 46 so as to be relatively rotatable. The guide member 46 is supported by the thrust bearing 48. Further, a male screw is formed on the outer peripheral surface of the intermediate portion of the screw shaft 24, and a substantially cylindrical nut 26 having a female screw formed on the inner peripheral surface is screwed into this portion. The nut 26 is fixed to the base end of an actuator rod 28 that is housed in the pipe holder 20B so as to be movable in the axial direction. Therefore, when the screw shaft 24 rotates around its axis, the nut 26 relatively moves axially on the screw shaft 24, whereby the actuator rod 28 integrated with the nut 26 moves axially. is there.

A joint 50 is attached to the tip of the actuator rod 28, and the tip of the actuator rod 28 is hung from the back surface near the lower end of the backrest plate 16 through the joint 50. It is connected to the connecting member 52 (see FIG. 1) so as to be relatively rotatable.

Further, the driving force transmission mechanism portion 32 is accommodated in the driving force transmission mechanism accommodation portion 38C of the resin plate 38. The driving force transmission mechanism unit 32 is the motor unit 2 described above.
The input gear 54 is interposed between the expansion mechanism 2 and the expansion / contraction mechanism 30 and meshes with the reduction gear 44 of the motor 22 and has a diameter larger than that. The input gear 54 is axially supported so as to be rotatable relative to the base end portion of the screw shaft 24. Therefore, even if the input gear 54 rotates, the screw shaft 24 does not rotate around its axis.

A first sun gear 56 is fixed to the base end portion of the screw shaft 24 adjacent to the input gear 54. Therefore, when the first sun gear 56 rotates about its axis, the screw shaft 24 also rotates in the same direction. The second sun gear 58, which has the same radial dimension as the first sun gear 56 but has a different number of teeth from the first sun gear 56, is adjacent to the position adjacent to the first sun gear 56. It is arranged. Therefore, the planetary gear device of this embodiment including the planetary gear 60 described below constitutes a mysterious planetary gear device. It should be noted that the second sun gear 58 has a base end portion 6 of an external input shaft 66, which will be described later.
6A is press-fitted to the outer peripheral portion of the external input shaft 6
It may be formed integrally with the outer peripheral portion of the base end portion 66A of No. 6.

Three planetary gears 60 arranged at 120 ° intervals are arranged in mesh with each other on the outer peripheral portions of the above-mentioned first sun gear 56 and second sun gear 58. Each planetary gear 60 has an axial length that is equal to the sum of the thicknesses of both the first sun gear 56 and the second sun gear 58, and the aforementioned input gear 54 and the holding plate arranged to face it. 62
And a planetary gear shaft 64, which is bridged between the two. The holding plate 62 is disposed near the root of the intermediate shaft portion 66B of the external input shaft 66, which will be described later. Therefore, the first sun gear 56 and the second sun gear 5 are provided between the input gear 54 and the holding plate 62.
8 and a plurality (in this embodiment, three) planetary gears 60
Are housed and arranged.

A clutch mechanism portion 34 is accommodated in the clutch mechanism accommodating portion 38D of the resin plate 38 described above. The clutch mechanism unit 34 includes the external input shaft 6
6 is provided. As shown in FIG. 4, the external input shaft 66 has a cylindrically shaped base end portion 66A to which the second sun gear 58 is mounted on the outer peripheral portion, and is erected from the axial center portion of the base end portion 66A. The intermediate shaft portion 66B has an outer peripheral surface that is a smooth surface, and a tip shaft portion 66C that is formed coaxially with the intermediate shaft portion 66B and that has peripheral surfaces that are flat-cut and that face each other.

A circular recess 68, which is viewed in the axial direction, is formed at the axial center of the base end 66A of the external input shaft 66 constructed as described above, and the base end of the screw shaft 24 is coaxial with the recess 68. (See FIG. 2). Also,
The intermediate shaft portion 66B of the external input shaft 66 is rotatably supported by a bearing 70 arranged in the clutch mechanism housing portion 38D. In addition, the external input shaft 6
A pair of engagement pins 72 are formed on the peripheral surface of the tip shaft portion 66C of No. 6 so as to project in the axis-perpendicular direction.

On the other hand, the outer end of the clutch mechanism accommodating portion 38D of the resin plate 38 is formed into a bottomed cylindrical shape, and the outer housing 74 is fitted (fixed) in the open portion. The outer housing 74 is formed in a flat bottomed cylindrical shape. This outer housing 74
A circular hole 76 is formed at the center of the bottom of the, and a rotation-stopping key 82 is radially and integrally formed around the circular hole 76.

A clutch member 80 is inserted inside the outer housing 74 having the above structure. As shown in FIG. 5, the clutch member 80 includes an outer housing 74.
A disk-shaped base portion 80A attached to the bottom of the
By the shaft portion 80B which is erected from the shaft center portion of 0A and is inserted into the circular hole 76 of the outer housing 74, and the cylindrical cam portion 80C which is coaxially extended from the shaft center portion of the shaft portion 80B. It is configured. On the front surface side of the base portion 80A, the key 8 is inserted between the keys 82 of the outer housing 74 to stop the rotation of the clutch member 80 around the axis.
4 are formed radially. Also, the shaft portion 80B
A shaft insertion hole 86 into which the tip shaft portion 66C of the external input shaft 66 is inserted is formed in the axial center portion of the cylindrical cam portion 80C. Furthermore, the cylindrical cam portion 80
Arc-shaped engaging grooves 88 are formed on both sides of C. The pair of engagement pins 72 of the external input shaft 66 described above are inserted into the engagement grooves 88.

A return spring (compression coil spring) 90, which is broadly understood as "biasing means", is wound around the outer peripheral portion of the intermediate shaft portion 66B of the external input shaft 66. As shown in FIG. 2, one end of the return spring 90 is abutted and locked on the bottom of the clutch mechanism housing portion 38D. On the other hand, the other end of the return spring 90 has a base portion 80 of the clutch member 80.
The end surface of A is abutted and locked. Therefore, the return spring 90 connects the clutch member 80 to the outer housing 74.
The pressure is constantly urged toward the side (the direction in which both keys 82 and 84 are engaged).

In the state where the above-mentioned clutch mechanism portion 34 is assembled, the tip shaft portion 66C of the clutch member 80.
Are protruded from the outer housing 74 and are arranged so as to be exposed to the outside. The release handle 92 shown in FIG. 2 can be fitted to the tip shaft portion 66C. The release handle 92 that constitutes the manual operation mechanism portion 36 includes a grip portion 90A that is arranged in parallel with the screw shaft 24, and an arm portion 90B that extends from the root of the grip portion 90A to the axial center side. Has been done. A fitting hole 94 into which the tip shaft portion 66C of the clutch member 80 can be fitted is formed in the tip portion of the arm portion 90B.

Next, the operation and effect of this embodiment will be described.

In a normal state, the motor portion 22 may be driven to raise the backrest plate 16 from the horizontal position.
As shown in FIG. 2, the motor body 40 of the motor unit 22
When is driven, the output shaft 40A rotates around its axis. Since the pinion gear 42 is fixed to the output shaft 40A, when the output shaft 40A rotates, the pinion gear 42
Also rotate in the same direction. Therefore, the reduction gear 44 meshed with the pinion gear 42 is rotated, and the reduction gear 4 is further rotated.
4 is engaged with the input gear 54 is the screw shaft 2
It is rotated around 4.

When the input gear 54 of the driving force transmission mechanism 32 rotates, the holding plate 62 connected via the planetary gear shaft 64 rotates integrally with the input gear 54. For this reason,
The planetary gear 60, which is supported by the planetary gear shaft 64, revolves around the outer circumferences of the first sun gear 56 and the second sun gear 58 while revolving.

At this time, that is, in a normal state, the key 84 of the clutch member 80 is engaged with the key 82 of the outer housing 74 by the urging force of the return spring 90 of the clutch mechanism portion 34, so that the clutch member 80 is moved to the outer housing 74. It is in a state where it cannot rotate relative to the so-called (so-called locked state). Therefore, the external input shaft 66 does not rotate around its axis, and therefore the second sun gear 58 also does not rotate. From the above, the rotational force generated by the planetary gear 60 is transmitted only to the first sun gear 56, which causes the first sun gear 56 to rotate by an amount corresponding to the difference in the number of teeth with the second sun gear 58.

The first sun gear 56 is the screw shaft 2
Since the first sun gear 56 is rotated, the screw shaft 24 is rotated around its axis. Therefore, the nut 26 screwed onto the screw shaft 24 moves axially along the screw shaft 24. As a result, the actuator rod 28 integrated with the nut 26 is axially moved (extended) in the direction away from the screw shaft 24. As a result, the connecting member 52 of the backrest plate 16 connected to the tip of the actuator rod 28 is pressed in the direction of arrow A in FIG. 1, and the backrest plate 16 is rotated in the direction of arrow B in FIG. Thereby, as shown in FIG. 1, the backrest plate 1
6 is raised at a predetermined inclination angle. At this time, the reaction force of the actuator rod 28 acts on the screw shaft 24 in the direction opposite to the arrow A direction in FIG. 1, but the reaction force is transmitted via the guide member 46 to the thrust bearing 48.
There is no problem because it is supported by.

On the other hand, in order to return the backrest plate 16 to the original horizontal state, the motor section 22 may be driven in reverse.

Here, when it is urgently desired to return the backrest plate 16 to the horizontal state in the event of a power failure or failure of the electric system, the backrest plate 16 is manually operated by using the release handle 92 in the following manner. It is returned to its original horizontal state.

That is, first, the tip shaft portion 66C of the clutch member 80 is fitted into the fitting hole 94 of the release handle 92. In the state immediately after the fitting, since the biasing force of the return spring 90 acts on the clutch member 80,
The pair of engagement pins 72 is in a state of being held in the intermediate portion of the pair of engagement grooves 88 (the state shown in FIG. 1). From this state, when the grip portion 90A is gripped and the release handle 92 is rotated by a predetermined amount, the pair of engagement pins 72 are pushed by the slopes of the pair of engagement grooves 88 and relatively move to the ends of the engagement grooves 88. Try to move to. As a result, the clutch member 80 is pressed against the biasing force of the return spring 90 and moves in a direction away from the outer housing 74, and the engagement state between the key 82 and the key 84 is released. That is, the drive force transmission path by the motor unit 22 at the normal time is cut off.

When the key 84 of the clutch member 80 is disengaged from the key 82 of the outer housing 74 by the above operation, the external input shaft 66 becomes rotatable about its axis. Therefore, by rotating the release handle 92 as it is (that is, with the engagement pin 72 abuttingly locked to the end of the engagement groove 88), the external input shaft 66 is rotated.
Rotates about its axis, and the second sun gear 58 integrated with this rotates in the same direction. When the second sun gear 58 rotates, the planet gear 60 meshing with the second sun gear 58 rotates at that position, and this rotational force is transmitted to the first sun gear 56. That is, the second sun gear 58 through the planetary gear 60
And the first sun gear 56 are directly connected. This makes the first
The sun gear 56 rotates, the screw shaft 24 rotates about its axis, and the actuator rod 28 is axially moved via the nut 26 in a direction in which the actuator rod 28 contracts. As a result, the backrest plate 16 is returned to its original horizontal state.

In the above case, the second sun gear 58 can rotate relative to the holding plate 62, and the first sun gear 56 can rotate relative to the input gear 54. Even if the gear 56 rotates, the input gear 54 does not rotate. Therefore, the load of the motor unit 22 is not added to the operation load of the release handle 92.

When the drive force transmission path by the motor section 22 is to be restored again, the release handle 92 may be removed from the clutch member 80. As a result, the clutch plate 80 is re-energized by the urging force of the return spring 90.
Key 84 of the outer housing 74 is engaged with the key 82 of the outer housing 74.

As described above, in the linear actuator 18 according to this embodiment, the driving force of the motor section 22 is normally the input gear 54 of the driving force transmission mechanism section 32, the planetary gear 60,
It is configured to be transmitted to the screw shaft 24 of the expansion and contraction mechanism unit 30 via the first sun gear 56, and the operating force by the release handle 92 during the manual operation is adjusted by the external input shaft 66 of the clutch mechanism unit 34 and the driving force transmission mechanism unit 32. It is configured to be transmitted to the screw shaft 24 of the expansion mechanism 30 via the second sun gear 58, the planetary gear 60, and the first sun gear 56 (that is, the first sun gear 56 and the second sun gear 58.
Since the and are directly connected via the planetary gear 60), it is possible to disconnect the load of the motor unit 22 when the actuator rod 28 is expanded and contracted by a manual operation during a power failure or the like. As a result, according to the present embodiment, the time required for manual operation of the linear actuator 18 can be made very good.

Moreover, in the case of the linear actuator 18 according to this embodiment, the first sun gear 56, the second sun gear 58, the planet gear 60, and the input gear 54 configured as described above.
By adopting such a configuration that the driving force of the motor unit 22 is decelerated and transmitted to the expansion / contraction mechanism unit 30 by using such a planetary gear device, even if the gears are not disengaged from each other, the driving force transmission path is interrupted (switched )It can be performed. Therefore, due to the mutual switching between normal operation and manual operation being performed several times,
It is possible to prevent problems such as damage to the gear teeth from occurring. As a result, according to this embodiment, there is also an advantage that the durability and reliability of the linear actuator 18 can be improved.

Further, in the linear actuator 18 according to this embodiment, the number of teeth of the first sun gear 56 and the number of teeth of the second sun gear 58 are set to be different from each other.
Since the mysterious planetary gear device is configured, a large reduction gear ratio can be obtained.

In addition, in this embodiment, the backrest plate 16 is rotatably connected to the bed frame 12, and the backrest plate 16 is rotated between a horizontal position and a position raised by a predetermined angle. Since the linear actuator 18 having the above-described configuration is applied to the bed 10, the tilted state can be obtained by manually operating the linear actuator 18 in an emergency such as a sudden change in the condition of the person requiring care at the time of power failure or failure. The backrest plate 16 can be quickly brought into a horizontal state.

In the linear actuator 18 according to the present embodiment, the release handle 92 is formed separately from the outer housing 74. However, the release handle 92 is not limited to this, and as shown in FIG. 80
It may be provided integrally with.

Further, in the linear actuator 18 according to this embodiment, the keys 82 and 84 are provided on the clutch member 80 and the outer housing 74, respectively, as the clutch mechanism portion 34.
However, the present invention is not limited to this, and another clutch mechanism may be adopted.

Further, in the linear actuator 18 according to the present embodiment, from the viewpoint of structural stability, the input gear 5
Although the holding plate 62 is arranged at a position opposed to No. 4, the holding plate 62 may be omitted as long as the reliability of rotation of the planetary gears 60 can be secured.

Further, the care bed 10 according to the present embodiment.
Then, the backrest plate 16 is configured to be rotated in the rising direction from the horizontal position by the extension of the actuator rod 28 of the expansion and contraction mechanism section 30. This is because the actuator rod 28 and the coupling member 52 on the backrest plate 16 side. This is because the and are directly connected, and the backrest plate 16 may be configured to rotate in the rising direction from the horizontal position by the contraction of the expansion and contraction mechanism section 30. Such a configuration is possible by interposing another member between the actuator rod 28 and the connecting member 52 of the backrest plate 16.

Further, the care bed 1 according to the present embodiment.
In No. 0, the backrest plate 16 can be raised by a predetermined angle with respect to the bed frame 12, but the linear actuator 18 according to the present invention is applicable to various types of care beds. .

FIG. 7 shows a care bed 100 according to another embodiment. In this care bed 100, a bed frame 104 is arranged in parallel with a gantry 102 installed on the floor. Bed frame 10
4 is provided with a backrest 106 in the horizontal portion 104A, and the hinge 14 is provided near the lower end of the backrest 106.
It is rotatably connected to the horizontal portion 104A via.
Further, the lower end of the backrest portion 106 is provided on the back surface side of the horizontal portion 104A of the bed frame 104 (first portion).
The tip of the actuator rod 28 of the linear actuator 18 is connected so as to be relatively rotatable.

A foot rest 108 is provided on the horizontal portion 104A of the bed frame 104 having the above-mentioned structure on the side opposite to the backrest 106. The foot rest 108 has a length about half that of the bed frame 104, and is configured by hinge-connecting two plate members 108A and 108B. The hinge joint portion 110 is a portion corresponding to the knee, and the footrest portion 108 is bendable from the hinge joint portion 110 as a starting point. Further, the buttocks side end of the footrest portion 108 is rotatably connected to the horizontal portion 104A. Further, the foot rest 10
A short connecting member 112 is hung on the back surface of the portion corresponding to the calf of FIG. 8, and the tip end of the actuator rod 28 of the (second) linear actuator 18 is relatively rotatable at the lower end of the connecting member 112. It is connected.

Further, the bed frame 104 having the above structure
Has a plurality of legs 104B, and the legs 104B
Are arranged in parallel to the legs 102A that are erected from the frame 102. A swinging link 114, which is substantially L-shaped in a side view, is used to connect the legs 104B and 102A. Specifically, the bent portion of the swing link 114 is rotatably connected to the lower end portion of the leg portion 104B of the bed frame 104, and one end portion is relatively connected to the upper end portion of the leg portion 102A of the gantry 102. It is rotatably connected. Further, the other ends of the swing links 114 are connected to each other by parallel links 116 arranged parallel to the horizontal portion 104A of the bed frame 104 so as to be relatively rotatable. Then, the (third) linear actuator 18 is provided on the other end side of the one swing link 114.
The base ends of are connected so as to be rotatable relative to each other. The tip end of the actuator rod 28 of the linear actuator 18 is relatively rotatably connected to the lower end of another connecting member 118 that hangs from the horizontal portion 104A of the bed frame 104.

According to the above construction, the actuator rod 28 extends in the direction of arrow A by the operation of the (first) linear actuator 18, and the backrest 106 is rotated around the hinge 14 in the direction of arrow B. . In addition, when the (second) linear actuator 18 operates, the actuator rod 28 extends in the direction of arrow C,
The foot rest 108 is bent in the direction of the arrow D around the hinge joint portion 110. Further, by operating the (third) linear actuator 18, the actuator rod 28 is relatively expanded and contracted in the arrow E direction. Therefore, the pair of swing links 11 are connected via the parallel links 116.
4 is swung clockwise (direction of arrow F). as a result,
The horizontal portion 104A of the bed frame 104 is raised in the arrow G direction.

The backrest portion 106 and the footrest portion 10
8. When moving the bed frame 104 in the direction opposite to the arrow B direction, the direction opposite to the arrow D direction, and the direction opposite to the arrow G direction, the (first) linear actuator 18 to
The (third) linear actuator 18 may be operated in reverse.

As described above, the linear actuator according to the present invention can realize various operations in the care bed. In addition, in addition, when a plurality of linear actuators are used for one bed as in the above-described embodiment, the arrangement directions of the manual operation mechanism unit in the present invention are all the same direction (that is, the tip side). Is preferred. This is because, in a hospital, a bed is generally arranged so that its head is directed toward the wall.

Further, in the present embodiment, the linear actuator 18 is applied to the care bed 10, but the present invention is not limited to this, and the linear actuator 18 may be applied to other devices.

[Brief description of drawings]

FIG. 1 is a side view schematically showing a main part of a nursing bed according to the present embodiment.

FIG. 2 is a cross-sectional view showing the internal structure of the linear actuator according to the present embodiment.

3 is a cross-sectional view taken along line 3-3 of FIG. 2 showing a gear configuration of the linear actuator shown in FIG.

4 is an exploded perspective view of the clutch mechanism portion shown in FIG. 2. FIG.

5 is a perspective view showing a state where the clutch member shown in FIG. 4 is viewed from another angle.

FIG. 6 is a sectional view corresponding to FIG. 2, showing another embodiment in which a release handle is integrated with a clutch member.

FIG. 7 is a side view schematically showing a main part of a nursing bed according to another embodiment.

[Explanation of symbols]

10 Care beds 12 bed frame (bed body) 14 Hinge 16 Back plate (back part) 18 Linear actuator 22 Motor part 24 Screw shaft (output shaft) 26 Nut (moving body) 28 Actuator rod 30 Telescopic mechanism 32 Driving force transmission mechanism 34 Clutch mechanism 36 Manual operation mechanism 54 input gear 56 First Sun Gear 58 Second Sun Gear 60 planetary gears 66 External input shaft 92 Release handle (manual operation mechanism) 96 release handle (manual operation mechanism) 100 nursing beds 102 mount 104 bed frame (bed body) 106 Backrest 108 Footrest

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J027 FA50 FB40 GB05 GC15 GC22                       GD03 GD09 GE29                 3J062 AA60 AB06 AB29 AC07 BA35                       CB06 CB14 CG04 CG13 CG83                       CG95                 4C040 AA05 BB01 BB06 DD04 DD05                       EE05

Claims (5)

[Claims] 1. A motor unit that is driven and rotated by being actuated, and an expansion / contraction mechanism unit that axially moves a moving body by rotating an output shaft around an axis and expands and contracts an actuator rod by the axial movement of the moving body. And a drive force transmission mechanism unit that is provided between the motor unit and the expansion / contraction mechanism unit and reduces the rotation speed of the motor unit and then transmits it to the expansion / contraction mechanism unit. A clutch mechanism section that sometimes allows the driving force transmission mechanism section to transmit the driving force, and cuts off the driving force transmission path between the motor section and the driving force transmission mechanism section during operation, and a clutch mechanism section that can be externally connected And a manual operation mechanism section for operating the clutch mechanism section by performing a predetermined manual operation, wherein the clutch mechanism section is An external input shaft that is arranged coaxially with the output shaft and that is normally prevented from rotating about its axis and that is allowed to rotate about its axis during manual operation by the manual operating mechanism is provided with the drive force. The transmission mechanism includes a first sun gear that rotates integrally with the output shaft, a second sun gear that rotates integrally with the external input shaft, and a planet that meshes with both the first sun gear and the second gear. A gear, and an input gear that rotatably supports the planetary gear, is coaxially and relatively rotatable with respect to the output shaft, and further receives the rotational force of the motor unit to rotate around the output shaft. The linear actuator is characterized in that: 2. The linear actuator according to claim 1, wherein the number of teeth of the first sun gear and the number of teeth of the second sun gear are set to be different from each other. 3. The nursing bed according to claim 1, wherein the backrest is rotatably connected to the bed body, and the backrest is rotated between a horizontal position and a position raised by a predetermined angle. The care bed, wherein the linear actuator according to claim 2 is applied. 4. A nursing care product in which a footrest portion is flexibly connected to a bed body with a portion corresponding to a knee as a starting point, and the footrest portion is bent between a horizontal position and a position bent at a predetermined angle. A nursing bed, wherein the linear actuator according to claim 1 or 2 is applied to a bed. 5. A nursing care bed in which a bed body is movably connected to a pedestal supported on a floor so that the bed body can be raised and lowered between a most lowered position and a most raised position. The linear actuator according to claim 1 or 2 is applied to the nursing bed.