JP5845026B2 - Load compensation mechanism - Google Patents

Description

  The present invention relates to a load compensation mechanism.

The present applicant has published a load compensation mechanism in Non-Patent Document 1. Although the basic principle of the load compensation mechanism will be described in detail in the embodiment, a first action point where a load acts on the rotating body and a second action point where the elastic force of the first elastic body acts on the rotating body. An operating point and a third operating point at which the elastic force of the second elastic body acts on the rotating body, and a torque around the rotational axis of the rotating body based on a load acting on the first operating point; Rotation direction in which the resultant force of the torque around the rotation axis of the rotating body based on the elastic force acting on the second action point and the resultant torque around the rotation axis of the rotating body based on the elastic force acting on the third action point are opposite directions It is the structure which acts on and cancels.
Here, the load compensation mechanism is configured to be able to cope with a change in the load by introducing an initial elastic force into the second elastic body.

The Japan Society of Mechanical Engineers Robotics and Mechatronics Lecture 2010 Proceedings, 2P1-D11, June 16, 2010

The load compensation mechanism configured as described above needs to introduce an initial elastic force to the second elastic body in response to a change in the load. However, as the load increases, a large amount of force is required to introduce the initial elastic force. become.
An object of the present invention is to provide a load compensation mechanism that can reduce the labor for introducing an initial elastic force.

  A load compensation mechanism according to an aspect of the present invention includes a first action point where a load acts on a rotating body, a second action point where an elastic force of a first elastic body acts on the rotating body, and the rotation A third action point at which the elastic force of the second elastic body acts on the body, and a torque around the rotation axis of the rotating body based on the load acting on the first action point; And the resultant torque of the torque around the rotation axis of the rotating body based on the elastic force acting on the third action point is opposite to the torque around the rotation axis of the rotating body based on the elastic force acting on the action point A load compensation mechanism that cancels out by acting in the rotational direction of the first elastic force, and includes an initial elastic force introducing mechanism that introduces an initial elastic force into the second elastic body.

  In the load compensation mechanism, the initial elastic force introducing mechanism includes a third elastic body, a fourth action point that is an action point opposite to the third action point in the second elastic body, A fifth operating point at which the elastic force of the third elastic body acts, a link mechanism connecting the fourth operating point and the fifth operating point, and a direction other than the expansion / contraction direction of the second elastic body A restraining mechanism for restraining movement, and when an initial elastic force is introduced into the second elastic body, based on a restoring force generated in the second elastic body and an elastic force of the third elastic body, It is preferable that the force acting on the second elastic body cancels out.

In the load compensation mechanism, it is preferable that an elastic coefficient of the second elastic body is equal to an elastic coefficient of the third elastic body.
In the load compensation mechanism, it is preferable that the second elastic body and the third elastic body are arranged in parallel.
In the load compensation mechanism, it is preferable that the second elastic body and the third elastic body are arranged so as to be orthogonal to each other.

  In the load compensation mechanism, the initial elastic force introduction mechanism is driven to a fourth action point that is an action point opposite to the third action point in the second elastic body, and to the fourth action point. A cam mechanism for transmitting force, and a restraining mechanism for restraining movement of the second elastic body in a direction other than the expansion / contraction direction, and when the cam body of the cam mechanism rotates, the restoring force of the second elastic body It is preferable that the cam shape of the cam body is set so that the torque generated in the cam body is constant.

  As described above, according to the present invention, it is possible to provide a load compensation mechanism that can reduce the labor for introducing the initial elastic force.

It is a figure which shows typically the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure explaining the displacement of the 2nd and 3rd action point in the load compensation mechanism of Embodiment 1 concerning the present invention. It is a figure which shows the simple model of the initial stage elastic force introduction | transduction mechanism in the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure which shows one form of the 3rd elastic body connected with the simple model of FIG. It is a figure which shows one different form of the 3rd elastic body connected with the simple model of FIG. It is a figure which shows the different simple model of the initial stage elastic force introduction mechanism in the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure which shows the different simple model of the initial stage elastic force introduction mechanism in the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure which shows the different simple model of the initial stage elastic force introduction mechanism in the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure which shows the different simple model of the initial stage elastic force introduction mechanism in the load compensation mechanism of Embodiment 1 which concerns on this invention. It is a figure which shows typically the load compensation mechanism of Embodiment 2 which concerns on this invention. It is a figure for demonstrating each parameter of a 2nd elastic body and a cam main body. It is a figure for demonstrating each parameter of a cam main body. It is a figure which shows an example of the cam shape of a cam main body. It is a figure which shows the relationship between the displacement of the lower end part of a 2nd elastic body, and the torque which a cam main body expresses. It is a figure which shows typically a different cam main body in the load compensation mechanism of Embodiment 2 which concerns on this invention. It is a figure which shows arrangement | positioning of the 2nd and 3rd action point, and arrangement | positioning of the 1st and 2nd elastic body in the load compensation mechanism of the other form which concerns on this invention. It is a figure which shows arrangement | positioning of the 2nd and 3rd action point, and arrangement | positioning of the 1st and 2nd elastic body in the load compensation mechanism of the other form which concerns on this invention. It is a figure which shows arrangement | positioning of the 2nd and 3rd action point, and arrangement | positioning of the 1st and 2nd elastic body in the load compensation mechanism of the other form which concerns on this invention. It is a figure which shows arrangement | positioning of the 2nd and 3rd action point, and arrangement | positioning of the 1st and 2nd elastic body in the load compensation mechanism of the other form which concerns on this invention. It is a front perspective view which shows roughly the raising / lowering apparatus to which the load compensation mechanism which concerns on this invention is applied. FIG. 3 is a front perspective view schematically showing the periphery of a first link in a lifting device to which a load compensation mechanism according to the present invention is applied. FIG. 4 is a front perspective view schematically showing the vicinity of second and third links in a lifting apparatus to which a load compensation mechanism according to the present invention is applied. It is a plane perspective view which shows roughly the initial stage elastic force introduction mechanism in the raising / lowering apparatus to which the load compensation mechanism based on this invention is applied.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Incidentally, in the following description, the direction parallel to the direction in which the load mg acts is the Y-axis direction, and the direction orthogonal to the Y-axis direction is the X-axis direction.

<Basic principle>
First, the basic principle of the load compensation mechanism will be described. In this principle, as shown in FIG. 1, the link 1 that is a rotating body is arranged in the Y-axis direction. The link 1 rotates around the rotation axis O1. One end of the link 1 is provided with a first action point P at which a load mg (hereinafter simply referred to as mg) acts.

  At the other end of the link 1, a second action point A where the elastic force of the first elastic body 2 acts is provided. The first elastic body 2 is disposed in the X-axis direction. For example, a coil spring can be used as the first elastic body 2, but a member such as rubber having an elastic coefficient may be used. One end of the first elastic body 2 is connected to the base 3. The other end of the first elastic body 2 is in contact with the second action point A. The first elastic body 2 is arranged so that the elastic force becomes zero (natural length) in a state where the link 1 is not rotating, that is, in a state where the first elastic body 2 is arranged in the Y-axis direction in FIG. Incidentally, in FIG. 1, in order to clearly show the arrangement of the link 1, the arrangement position of the first elastic body 2 is not accurately shown.

  Here, when the link 1 rotates around the rotation axis O1, the allowance part 4 that allows the displacement of the link 1 in the Y-axis direction is prevented so that the first elastic body 2 is not twisted in the Y-axis direction. It is preferable to provide. The allowable portion 4 includes a protruding portion 4 a that protrudes from the second action point A in the Z-axis direction, and a sliding plate 4 b provided at the other end of the first elastic body 2. As a result, as shown in FIG. 1, when mg acts on the first action point P of the link 1 and the link 1 rotates in the direction of arrow N, the protruding portion 4a slides on the sliding plate 4b. Then, the sliding plate 4b is pushed in. Therefore, the first elastic body 2 is not twisted following the rotation of the link 1. Incidentally, it is preferable that the protrusion 4a includes a roller. Thereby, the protrusion part 4a can be smoothly moved on the sliding plate 4b.

  On the link 1, the elastic force of the second elastic body 5 is placed on the rotation axis O 1 and the second action point A, that is, on the straight line L 1 connecting the first action point P and the second action point A in this principle. A third action point B at which is applied is provided. The third action point B is arranged at a position between the rotation axis O1 and the second action point A. The second elastic body 5 is disposed in the Y-axis direction. For example, a coil spring can be used as the second elastic body 5, but a member such as rubber having an elastic coefficient may be used. One end of the second elastic body 5 is connected to a restraining mechanism 10 described later. The other end of the second elastic body 5 is in contact with the third action point B. The second elastic body 5 is arranged so that the elastic force becomes zero (natural length) in a state where the link 1 is not rotating. Incidentally, in FIG. 1, in order to clearly show the arrangement of the link 1, the arrangement position of the second elastic body 5 is not accurately shown.

  Here, when the link 1 rotates around the rotation axis O1, the allowance part 6 that allows the displacement of the link 1 in the X-axis direction is prevented so that the second elastic body 5 is not twisted in the X-axis direction. It is preferable to provide. The allowing portion 6 includes a protruding portion 6 a that protrudes from the third action point B in the Z-axis direction, and a sliding plate 6 b provided at the other end of the second elastic body 5. As a result, as shown in FIG. 1, when mg acts on the first action point P of the link 1 and the link 1 rotates in the direction of arrow N, the protruding portion 6a slides on the sliding plate 6b. Then, the sliding plate 6b is pushed in. Therefore, the second elastic body 5 is not twisted following the rotation of the link 1. Incidentally, it is preferable that the protrusion 6a includes a roller. Thereby, the protrusion part 6a can be smoothly moved on the sliding plate 6b.

Rotational torque τ _P around the rotation axis O1 based on mg acting on the first action point P and rotation torque around the rotation axis O1 based on the elastic force of the first elastic body 2 acting on the second action point A The total torque of the rotational torque τ _B around the rotational axis O1 based on the elastic force of the second elastic body 5 acting on τ _A and the third operating point B is opposite to the rotational direction about the rotational axis O1. Act on. Therefore, if the rotational torque τ _P and the value obtained by adding the rotational torques τ _A and τ _B are equal, a mechanism for compensating mg is obtained.

Specifically, as shown in FIG. 2, if mg acts on the first action point P and the link 1 rotates about the rotation axis O1 in the direction of the arrow N by the rotation angle θ, The rotational torque τ _P around the rotational axis O1 based on mg acting on the point of action _P is expressed by [Expression 1].
[Formula 1] τ _P = mgl _P sin θ
However, the distance to the rotational axis O1 and l _P from the first working point P.

The displacement x in the X-axis direction of the first elastic body 2 at this time is expressed by [Expression 2].
[Formula 2] x = l _A sin θ
However, the distance from the second action point A to the rotation axis O1 is l _A.
Further, the displacement y in the Y-axis direction of the second elastic body 5 is expressed by [Expression 3].
[Formula 3] y = l _B (1-cos θ)
However, the distance from the third action point B to the rotation axis O1 is assumed to be 1 _B.

Therefore, the force f _A acting in the X-axis direction at the second action point _A is expressed by [Expression 4].
[Formula 4] f _A = k ₁ x = k ₁ l _A sin θ
However, the first elastic coefficient of the elastic body 2, k _1.
Further, the force f _B acting in the Y-axis direction at the third action point _B is expressed by [Expression 5].
[Formula 5] f _B = k ₂ y = k ₂ l _B (1-cos θ)
However, the elastic modulus of the second elastic member 5 and k _2.

Therefore, the rotational torque τ _A around the rotational axis O1 based on the elastic force of the first elastic body 2 acting on the second action point A is expressed by [Expression 6].
[Formula 6] τ _A = k ₁ l _A ² sin θ cos θ
Further, the rotational torque τ _B around the rotational axis O1 based on the elastic force of the second elastic body 5 acting on the third action point B is expressed by [Expression 7].
[Expression 7] τ _B = k ₂ l _B ² (1-cos θ) sin θ

Therefore, the total torque (synthetic torque) τ _k of the rotational torques τ _A and τ _B is expressed by [Equation 8].
[Expression 8] τ _k = k ₁ l _A ² sin θ cos θ + k ₂ l _B ² (1−cos θ) sin θ
Here, when k ₁ l _A ² = k ₂ l _B ² , [Expression 8] is expressed by [Expression 9].
[Expression 9] τ _k = k ₂ l _B ² sin θ
Therefore, the force ω acting upward is expressed by [Formula 10].
[Expression 10] ω = τ _k / (l _p sin θ) = k ₂ l _B ² / l _p
Thereby, the above-described principle can make the force acting upwards constant.

Further, assuming that k ₁ l _A ² = k ₂ l _B ² = C, [Expression 8] is expressed by [Expression 11].
[Formula 11] τ _k = C sin θ
Therefore, from Expression 1, it satisfies a C = mgl _p, mechanism that can compensate for mg can be realized.

In the design method of the load compensation mechanism described above, since the load can be compensated only up to mg, it is preferable to introduce an initial elastic force into the second elastic body 5.
That is, in order to introduce the initial elastic force to the second elastic body 5, the initial installation point (equilibrium point) is moved downward by l _B ′.

Thereby, [Formula 3] changes to [Formula 12].
[Formula 12] y = l _B (1-cos θ) + l _B ′
Here, 'a, _{l B} using _{l B' l B} is expressed as _{= l B (α-1)} , represented by [Expression 9] [Formula 13].
[Formula 13] τ _k = Cα sin θ

In this case, α = 1 means that the initial displacement l _B = 0, and mg is compensated. When α = 2, l _B ′ = l _B , and the load that can be compensated is doubled. In this way, the corresponding load can be adjusted only by introducing the initial elastic force to the second elastic body 5. Incidentally, if the second elastic body 5 is stretched and installed in advance, the corresponding load can be reduced. The reason for introducing the initial elastic force only to the second elastic body 5 is to make it possible to eliminate cos θ as described above. Therefore, an initial elastic force is introduced into the elastic body that generates a rotational torque in the y-axis direction.

  At this time, as the mg to be compensated increases, a large force is required to introduce the initial elastic force. Therefore, in this embodiment, the following configuration is adopted.

<Embodiment 1>
A load compensation mechanism according to the first embodiment will be described. As shown in FIG. 1, the load compensation mechanism of the present embodiment includes an initial elastic force introduction mechanism 7 in addition to the components described in the basic principle. The initial elastic force introducing mechanism 7 includes a third elastic body 8, a link mechanism 9, and a restraining mechanism 10.

  The third elastic body 8 is disposed substantially in parallel with the first elastic body 2. That is, the third elastic body 8 is arranged in the X-axis direction. One end of the third elastic body 8 is connected to the base 3. The other end of the third elastic body 8 is in contact with the link mechanism 9. The third elastic body 8 is set so that the elastic force becomes zero in a state where the other end is arranged on a straight line passing through a fourth action point C described later and extending in the Y-axis direction. Yes.

  The link mechanism 9 includes two links 9a and 9b having the same length. In the two links 9a and 9b, the connecting portion at one end of the links 9a and 9b moves in the X and Y axis directions, and the other end of the links 9a and 9b moves in the Y axis direction.

  Specifically, one end of the link 9a is coupled to one end of the link 9b so as to be rotatable about an axis parallel to the Z axis. The other end of the link 9a is coupled to the restraining mechanism 10 so as to be rotatable about an axis parallel to the Z axis. The other end of the link 9b is connected to the base 3 so as to be rotatable about an axis parallel to the Z axis. The other ends of the links 9a and 9b are arranged on a straight line that passes through a fourth action point C described later and extends in the Y-axis direction. That is, the link mechanism 9 is arranged in a V shape when viewed from the Z-axis direction.

  The connecting portion between the links 9 a and 9 b is in contact with the other end portion of the third elastic body 8. That is, the connecting portion between the links 9a and 9b functions as a fifth action point D where the elastic force of the third elastic body 8 acts.

  Here, the connecting portion between the links 9a and 9b preferably includes an allowance portion 11 that allows displacement of the connecting portion in the Y-axis direction. The allowing portion 11 includes a protruding portion 11 a that protrudes in the Z-axis direction from the connecting portion, and a sliding plate 11 b provided at the other end of the third elastic body 8. Thereby, although the details will be described later, when the second elastic body 5 is pushed in by the elastic force of the third elastic body 8 via the link mechanism 9, the protruding portion 11a slides on the sliding plate 11b. Therefore, the third elastic body 8 is not twisted in the Y-axis direction. Incidentally, it is preferable that the protrusion part 11a is provided with the roller. Thereby, the protrusion part 11a can be smoothly moved on the sliding plate 11b.

  The restraint mechanism 10 includes a linear guide 10a and a drive mechanism 10b. The linear guide 10a has the same configuration as a general linear guide. Specifically, the linear guide 10a is not specifically illustrated, but the sliding portion 10c moves along a rail member arranged in the Y-axis direction. Here, the rail member is connected to the base 3. The sliding portion 10c includes a protruding portion 10d that protrudes in the X-axis direction. That is, the sliding part 10c is formed in a substantially L shape when viewed from the Z-axis direction. One end of the second elastic body 5 is in contact with one surface (the lower surface in FIG. 1) arranged in the Y-axis direction of the protruding portion 10d. The other end (upper surface in FIG. 1) of the protrusion 10d arranged in the Y-axis direction is connected to the other end of the link 9a so as to be rotatable about an axis parallel to the Z-axis. That is, the connecting portion between the protruding portion 10 d and the link 9 a functions as a fourth action point C that is an action point on the opposite side of the third action point B in the second elastic body 5.

  Driving force is transmitted to the sliding portion 10c in the Y-axis direction from the driving mechanism 10b. For example, the drive mechanism 10b slides the driving force of the electric motor by screwing a pinion gear provided on the rotating shaft of an electric motor, which is an example of a driving device, with a rack gear or a ball screw connected to the sliding portion 10c. It is set as the structure transmitted to the part 10c. However, the configuration of the driving mechanism 10b is not particularly limited as long as the driving mechanism 10b can apply a driving force for moving the sliding portion 10c in the Y-axis direction to the sliding portion 10c.

  With such a configuration, the movement of the second elastic body 5 in a direction other than the expansion / contraction direction (Y-axis direction) is restrained. Therefore, the elastic force of the third elastic body 8 acts to push the second elastic body 5 downward through the link 9a.

Next, a description will be given of a principle that requires a small force when introducing the initial elastic force to the second elastic body 5 when the initial elastic force introducing mechanism 7 is used.
FIG. 3 shows a simple model of the initial elastic force introduction mechanism 7. The fourth action point C is restrained from moving in other directions by the linear guide 12 extending in the Y-axis direction. The fifth action point D is restrained from moving in other directions by the linear guide 13 extending in the X-axis direction. And the 4th action point C and the 5th action point D are connected by the link 9a. Further, as shown in FIG. 4, the third elastic body 8 arranged in the X-axis direction is connected to the fifth action point D.

Here, as shown in FIG. 3, the fourth point is the intersection point of a straight line that extends in the Y-axis direction through the fourth action point C and a straight line that extends in the X-axis direction through the fifth action point D. The displacement of the action point C in the Y-axis direction and the displacement of the fifth action point D in the X-axis direction are denoted as q ₁ and p ₁ . Incidentally, the elastic force of the third elastic body 8 is set to zero at the intersection position.

Under such conditions, the relationship of [Equation 14] is established from the three-square theorem.
[Formula 14] p ₁ ² + q ₁ ² = r ₁ ²
However, the length of the link 9a (the distance between the fourth point of action C in the fifth action point D) and r _1.
[Formula 14] can be derived by transforming [Formula 14].
[Formula 15] p ₁ = √ (r ₁ ² −q ₁ ² )
When partially differentiated Expression 15] in _{q 1,} the speed reduction ratio from _{q 1} to _{p 1} (Jacobian) J is expressed by [Formula ^{_{16] (p 1 (·)}} = Jq 1 (·)).
[Formula 16] J = −q ₁ / √ (r ₁ ² −q ₁ ² ) = − q ₁ / p ₁

Further, as shown in FIG. 3, when the inclination angle of the X-axis direction and the link 9a and phi _1, represented by the [formula 16] [Formula 17].
[Formula 17] J = −q ₁ / p ₁ = −tan φ ₁
With this Jacobian, [Equation 18] is established for force transmission.
[Formula 18] f _C = −f _D tanφ ₁
However, the elastic force of the third elastic body 8 acting on the fifth action point D is f _D and the force acting on the fourth action point C is f _C.

f _D is represented by [Equation 19].
[Formula 19] f _D = −k ₃ p ₁
However, the elastic coefficient of the third elastic body 8 is k ₃ .
At this time, the force f _C acting on the fourth action point _C is expressed by [Expression 20].
[Formula 20] f _C = k ₃ p ₁ tanφ ₁ = k ₃ q ₁

That is, the sign is inverted, the elastic coefficient remains the same, and the displacement is replaced by p ₁ to q ₁ . This is a matter already known, for example, as a “negative spring” in the field of vibration systems.

Here, one end of the second elastic body 5 shown in FIG. A downward force f _C from the third elastic body 8 and an upward force f _B from the second elastic body 5 act on the fourth action point C, and the upward force is positive. Then, the resultant force f _C ′ is expressed by [Expression 21].
[Expression _{21] f C '= f B} -f C = k 2 (q 1 + y) -k 3 q 1

Further, if the elastic coefficient of the third elastic body 8 is k ₃ = k ₂ , the resultant force acting on the fourth action point C (force necessary for moving the equilibrium point) is expressed by [Equation 22]. .
[Formula 22] f _C ′ = k ₂ y

Thus, required to move the equilibrium point force regardless of displacement q ₁ of the fourth action point C, it is determined by the displacement y of the other end of the second elastic member 5. That is, it acts on the second elastic body 5 based on the restoring force of the second elastic body 5 generated when the initial elastic force is introduced into the second elastic body 5 and the elastic force of the third elastic body 8. Power cancels out. Therefore, it is possible to introduce the initial elastic force to the second elastic body 5 with a small force compared to the case where the initial elastic force introducing mechanism 7 is not provided.

  In the link mechanism 9 of the above embodiment, the third elastic body 8 is arranged so as to push in the fifth action point D. However, as shown in FIG. 5, the fifth action point D is drawn. As described above, the third elastic body 8 can be arranged in the same manner.

In the link mechanism 9 of the above-described embodiment, the two links 9a and 9b are set to have the same length. However, like the link mechanism 91 shown in FIG. It may be extended. For example, in the link mechanism 91 of FIG. 6, the length of the link 91a is set to twice the length of the link 91b, and is connected to one end of the link 91b at an intermediate position. The other end of the link 91a is in contact with the other end of the third elastic body 8. In this case, if p ₁ = p ₂ , q ₁ = q ₂ , and r ₁ = r ₂ are replaced, the principle of the link mechanism 9 shown in FIG. 3 is the same. The link mechanism 9 of FIG. 1 is equivalent to the other end of the third elastic body 8 in contact with the intermediate position of the link 91a of FIG. Is 1/2 of p ₂ , so that the elastic coefficient of the third elastic body 8 is the second elasticity to cancel the restoring force of the second elastic body 5 by the restoring force of the third elastic body 8. It is set to twice the elastic coefficient of the body 5.

  Incidentally, as shown in FIG. 7, the third elastic body 8 is arranged in the Y-axis direction (however, the arrangement direction is not particularly limited), and the other end of the third elastic body 8 is connected to the pulley 14. You may connect with one edge part of the link 9a via this.

  Moreover, although the link mechanism 9 of the said embodiment has arrange | positioned 1 set of two links 9a and 9b, as shown in FIG. 8, two sets of link mechanisms 9 are arrange | positioned in parallel in the X-axis direction. The connecting portions of the links 9 a and 9 b may be connected by the third elastic body 8. Thereby, the swinging of the third elastic body 8 can be substantially prevented.

Moreover, although the link mechanism 9 of the said embodiment combines the two links 9a and 9b, the number of links is not specifically limited. That is, you may combine a some link like the link mechanism 92 shown in FIG. For example, the link mechanism 92 of FIG. 9 includes an L-shaped first link 92a and linear second and third links 92b and 92c. A corner portion of the first link 92a is coupled to the base 3 so as to be rotatable around an axis parallel to the Z axis. One end of the first link 92a is coupled to one end of the second link 92b so as to be rotatable about an axis parallel to the Z axis. The other end of the first link 92a is connected to one end of the third link 92c so as to be rotatable about an axis parallel to the Z axis. The other end of the second link 92b is connected to a linear guide 15 disposed in the Y-axis direction. That is, the movement of the other end portion of the second link 92 b in a direction other than the Y-axis direction is restricted by the linear guide 15. The other end of the third link 92c is coupled to the linear guide 16 disposed in the Y-axis direction. That is, the movement of the other end portion of the third link 92c in a direction other than the Y-axis direction is restricted by the linear guide 16. Here, the other end of the second link 92b and the other end of the third link 92c are disposed on a common straight line extending in the Y-axis direction. The other end portion of the third link 92 c is in contact with the other end portion of the third elastic body 8. The third elastic body 8 is arranged in the Y-axis direction, and one end thereof is connected to the base 3. Even in such a configuration, if p ₁ = p ₃ , q ₁ = q ₃ , and r ₁ = r ₃ are replaced, the principle of the link mechanism 9 described above is the same.

<Embodiment 2>
A load compensation mechanism according to the second embodiment will be described. As shown in FIG. 10, the load compensation mechanism of the present embodiment includes an initial elastic force introduction mechanism 71 in addition to the components that explain the basic principle. The initial elastic force introduction mechanism 71 includes a cam mechanism 72.

  The cam mechanism 72 includes a cam body 73 and a restraining mechanism 74. The cam body 73 is formed in a curved surface shape (cam shape) on an outer peripheral side surface, which will be described in detail later, and a restraining mechanism 74 is in contact with the outer peripheral side surface. The cam body 73 rotates when the driving force of a driving device (not shown) is transmitted to the rotating shaft 73a.

  The restraining mechanism 74 includes a linear guide 74a. The linear guide 74a has the same configuration as a general linear guide. That is, although the specific illustration of the linear guide 74a is omitted, the sliding portion 74b moves along the rail member arranged in the Y-axis direction. Here, the rail member is connected to the base 3. The sliding portion 74b includes a protruding portion 74c that protrudes in the X-axis direction. That is, the sliding part 74b is formed in a substantially L shape when viewed from the Z-axis direction.

  One end portion of the second elastic body 5 is in contact with one surface (the lower surface in FIG. 10) arranged in the Y-axis direction of the protruding portion 74c. The outer peripheral side surface of the cam main body 73 is in contact with the other surface (upper surface in FIG. 10) arranged in the Y-axis direction of the protruding portion 74c. That is, the contact portion between the protrusion 74 c and the cam body 73 functions as the fourth action point C. Incidentally, in the present embodiment, the projecting portion 74 c and the cam body 73 are in contact via the cam follower 75.

  With such a configuration, when the cam main body 73 is rotated, the second elastic body 5 is restrained from moving in a direction other than the expansion / contraction direction (Y-axis direction) and follows the cam shape of the cam main body 73. The second elastic body 5 is pushed downward. At this time, as described below, when the cam main body 73 is rotated, the torque generated in the cam main body 73 by the restoring force of the second elastic body 5 is constant in the set state. The cam shape should be designed.

Next, a cam shape design method for the cam body 73 will be described. FIGS. 11A, 11B, and 12 show parameters of the cam body 73. FIG. Ψ is the rotation angle of the cam body 73, R ₀ is the minimum radius of the cam body 73, R (ψ) is the distance (radius) between the fourth action point C and the rotation shaft 73a when the cam body 73 rotates Ψ, l _B ′ is the displacement of the upper end portion of the second elastic body 5 in the Y-axis direction, y is the displacement of the lower end portion of the second elastic body 5 in the Y-axis direction, dΨ is a minute angle, and RdΨ is the cam body 73. X-axis direction of the distance in small angle portion of the outer peripheral side in, dR is the distance in the Y-axis direction in the micro angle portion of the outer peripheral surface of the cam body 73, the phi ₂ inclination angle in the minute angle portion of the outer peripheral surface of the cam body 73, f _x is the X-axis direction on that end portion of the small angle portion of the outer peripheral surface of the cam body 73 force, f _y in the Y-axis direction of the force applied to one end of the small angle portion of the outer peripheral surface of the cam body 73 is there.

With such parameters, the second action point B is displaced by y (θ) in the Y-axis direction. Further, the fourth action point C is displaced by the cam main body 73 by l _B ′ (Ψ) in the Y-axis direction. Here, the radius of the cam body 73 when Ψ = 0 is R ₀ = R (0), and y (θ) is expressed by [Expression 23] (similar to [Expression 3]).
[Formula 23] y (θ) = l _B (1-cos θ)

Further, l _B ′ (Ψ) is expressed by [Equation 24].
[Formula 24] l _B ′ (Ψ) = R (Ψ) −R ₀
And the torque which acts on the cam main body 73 is represented by [Formula 25].
[Expression 25] τ = R (Ψ) f x
Here, [Formula 26] to [Formula 28] hold.
[Expression _{26] f x = f y tanφ} 2
[Formula 27] f _y = k ₂ (y (θ) + l _B ′ (Ψ))
[Formula 28] tanφ ₂ = dR / RdΨ

［式３０］を解くと、［式３１］を導くことができる。
［式３１］ τΨ＝ｋ_２（ｙＲ＋Ｒ^２／２−Ｒ_０Ｒ−ｙＲ_０＋Ｒ_０ ^２／２）
［式３１］をＲについて解くと、［式３２］を導くことができる。
［式３２］ Ｒ＝Ｒ_０−ｙ±√（ｙ^２＋２τΨ／ｋ_２） Therefore, [Equation 29] can be derived.
[Formula 29] τ = k ₂ (y + R−R ₀ ) dR / dΨ
[Equation 30] can be derived by separating and integrating [Equation 29].

[Equation 31] can be derived by solving [Equation 30].
[Expression ^{_{31] τΨ = k 2 (yR}} + R 2/2-R 0 R-yR 0 + R 0 2/2)
Solving [Expression 31] with respect to R yields [Expression 32].
[Formula 32] R = R ₀ −y ± √ (y ² + 2τΨ / k ₂ )

In this way, the cam shape of the cam body 73 as expressed by [Expression 32] can be derived. Here, for example, the elastic coefficient k ₂ = 28000 [N / m] of the second elastic body 5, the minimum radius R ₀ = 22 [mm] of the cam body 73, the torque setting value expressed by the driving device, that is, the cam body 73 The cam of the cam main body 73 obtained by the above [Equation 32], when the torque τ = 6.2 [N · m] to be expressed in the above and the displacement y = 20 [mm] of the lower end portion of the second elastic body 5 are set. The shape is as shown in FIG. Here, the angle is obtained up to 180 °, and the cam body 73 has a line-symmetric shape. However, the torque can be further reduced by obtaining one round.

  In the above-described example, the minimum radius R (0) = 22 [mm] and the maximum radius R (π) = 44 [mm] are adjusted by adjusting the torque τ applied to the cam body 73 to 6.2 [N · m]. ], 22 [mm] required for moving the equilibrium point can be secured.

When the torque required when the cam shape of the cam main body 73 is used is calculated backward, it is expressed by [Expression 33].
[Formula 33] τ = k ₂ ((R−R ₀ + y) ² −y ² ) / 2Ψ

  FIG. 14 shows how the torque required to rotate the cam body 73 changes when the displacement y of the lower end portion of the second elastic body 5 changes. Since the maximum displacement 20 [mm] of y is a design value, when y = 20 [mm], the set torque 6.2 [N · m] is constant, and when y is smaller than 20 mm, it is smaller than the torque. I can confirm that.

  By designing the cam shape of the cam main body 73 in this way, the second elastic body 5 can be pushed in under a preset torque under a condition where y is a preset maximum displacement or less. Therefore, it is possible to introduce the initial elastic force to the second elastic body 5 with a small force compared to the case where the initial elastic force introducing mechanism 71 is not provided.

The cam body 73 of the present embodiment has a cam shape that is line-symmetrical by obtaining the cam shape up to 180 °, but may be formed in a cam shape that is obtained up to 360 ° as shown in FIG. .
Here, [Equation 33] is the outer peripheral shape of the cam obtained by assuming that the diameter of the roller (cam follower 75) located at the fourth action point C is zero, and in the implementation, the outer peripheral shape is offset inward by the radius of the cam follower. Will be used.

<Other embodiments>
In the above principle, the second action point A and the third action point B are provided on the opposite side of the link 1 on the side where the first action point P is provided and the rotation axis O1. Not.

  For example, as shown in FIG. 16, a second action point A and a third action point B may be provided between the first action point P and the rotation axis O1 in the link 1.

  As shown in FIG. 17, when a T-shaped link 17 is used instead of the link 1, the first action point P and the third action point B are arranged at both ends across the rotation axis O <b> 2 of the link 17. And the second action point A may be provided on a straight line L3 orthogonal to the straight line L2 connecting the first action point P and the third action point B and passing through the rotation axis O2.

  Also, as shown in FIG. 18, when the T-shaped link 17 is used instead of the link 1, the first action point P and the second action point are arranged at both ends across the rotation axis O <b> 2 of the link 17. A may be provided, and the third action point B may be provided on a straight line L5 orthogonal to the straight line L4 connecting the first action point P and the second action point A and passing through the rotation axis O2.

  Further, as shown in FIG. 19, instead of the link 1, the L-shaped first link 18 and the linear second and third links 19 and 20 are used as follows. Three action points may be provided. Specifically, the first action point P is provided at one end of the first link 18. A rotation axis O3 is provided at the other end of the first side 18a of the first link 18. A sixth action point E is provided at a position between the rotation axis O <b> 3 and the first action point P in the first link 18. One end of the second link 19 is connected to the sixth action point E so as to be rotatable about an axis parallel to the Z axis. Although the specific illustration of the other end of the second link 19 is omitted, the second link 19 is configured to be slidable in the X-axis direction. The other end of the second link 19 is connected to the first elastic body 2 arranged in the X-axis direction. That is, the other end of the second link 19 functions as the second action point A. A seventh action point F is provided at the end of the second side 18 b of the first link 18. One end of the third link 20 is connected to the seventh action point F so as to be rotatable about an axis parallel to the Z axis. Although the specific illustration of the other end of the third link 20 is omitted, the third link 20 is configured to be slidable in the X-axis direction. Further, the other end of the third link 20 is connected to the second elastic body 5 arranged in the X-axis direction. That is, the other end of the third link 20 functions as the third action point B.

In short, the rotational torque around the rotation axis based on the elastic force of the first elastic body 2 acting on the second action point A with respect to the rotational torque around the rotation axis based on mg acting on the first action point P. And the second action so that the resultant torque of the rotation torque around the rotation axis based on the elastic force of the second elastic body 5 acting on the third action point B acts in the opposite rotation direction and becomes equal. What is necessary is just to change suitably the arrangement | positioning of the point A, the 3rd action point B, the 1st elastic body 2, and the 2nd elastic body 5, and an elastic coefficient.
<Application form>

  The form which applied the above-mentioned basic principle to the raising / lowering apparatus is demonstrated. As shown in FIGS. 20 to 23, the lifting device 100 according to this application mode includes a link mechanism 110, a base 120, a lifting platform 130, a first elastic body 140, a second elastic body 150, and an initial stage. And an elastic force introduction mechanism 160.

  The link mechanism 110 includes a linear first link 111, an L-shaped second link 112, and a linear third link 113. The first link 111 and the second link 112 are rotatably connected at the central portion in the longitudinal direction and arranged in an X shape. The second link 112 includes a first side 112a and a second side 112b orthogonal to the lower end of the first side 112a.

  As shown in FIG. 21, one end of the first link 111 is connected to the base 120 so as to be slidable in the X-axis direction. The other end of the first link 111 is connected to the lifting platform 130 so as to be rotatable about an axis parallel to the Z axis. As shown in FIG. 22, one end of the first side 112a of the second link 112 is connected to the elevator 130 so as to be slidable in the X-axis direction. The other end of the first side 112a of the second link 112 is coupled to the base 120 so as to be rotatable about an axis parallel to the Z axis. One end of the third link 113 is connected to the end of the second side 112b of the second link 112 so as to be rotatable about an axis parallel to the Z axis. The other end of the third link 113 is connected to the base 120 so as to be slidable in the X-axis direction.

  The base 120 includes a groove 121 that extends in the X-axis direction so that the other ends of the first and third links 111 and 113 can slide. A roller 111 a provided at the other end of the first link 111 and a roller 113 a provided at the other end of the third link 113 are inserted into the groove 121.

  The elevator 130 includes a groove 131 that extends in the X-axis direction so that one end of the first side 112a of the second link 112 can slide. A roller 112 c provided at one end of the first side 112 a of the second link 112 is inserted into the groove 131.

  The first elastic body 140 is disposed in the X-axis direction. One end of the first elastic body 140 is connected to the other end of the first link 111. The other end of the first elastic body 140 is connected to the base 120. The second elastic body 150 is also arranged in the X-axis direction. One end of the second elastic body 150 is connected to the other end of the third link 113. The other end of the second elastic body 150 is connected to the initial elastic force introducing mechanism 160. The first and second elastic bodies 140 and 150 are set so that the elastic force becomes zero when the first and second links 111 and 112 are not rotating, that is, when θ = 0 °. Incidentally, the first elastic body 140 is connected to the other end of the first link 111, which is connected to one end of the first side 112 a of the second link 112. Can be handled in the same way.

When the luggage 170 is placed on the lifting platform 130 of the lifting device 100 having such a configuration and is set to an arbitrary height, the first and second links 111 and 112 of the first and second elastic bodies 140 and 150 are not rotated. In this state, that is, θ = 0 °, and the elastic force is connected to be zero, the displacement x _{1 in} the X-axis direction of the other end of the first link 111 is expressed by [Expression 34]. .
[Formula 34] x ₁ = l ₁ sin θ
However, the length of the first link 111 is assumed to be l ₁ .
Further, X-axis direction displacement _{x 2} of the other end of the third link 113 is represented by [Expression 35].
[Formula 35] x ₂ = l ₂ (1-cos θ)
However, the length of the second side 112b of the second link 112 _l 2/2, the length of the third link 113 and _l 2/2.

  That is, in this embodiment, the other end of the first link 111 is made to correspond to the second action point A shown in FIG. 1, and the other end of the third link 113 is the third end shown in FIG. The lifting / lowering device 100 capable of compensating the load can be realized by designing based on the basic principle described above.

  Here, also in this embodiment, as shown in FIG. 23, the initial elastic force is applied to the second elastic body 150 by the initial elastic force introduction mechanism 160 having the same principle as the initial elastic force introduction mechanism shown in FIG. 9 described above. Introduce. Note that the broken line in FIG. 23 shows the operation of the initial elastic force introduction mechanism 160. The initial elastic force introducing mechanism 160 is housed in the base 120. The initial elastic force introduction mechanism 160 includes an L-shaped fourth link 161 having the same length of adjacent sides across the corner portion, and fifth and sixth links 162 and 163 having the same linear length. , A third elastic body 164, and the like.

  A corner portion of the fourth link 161 is connected to the base 120 so as to be rotatable around an axis parallel to the Y axis. One end of the fourth link 161 is connected to one end of the fifth link 162 so as to be rotatable about an axis parallel to the Y axis. The other end of the fifth link 162 is connected to the other end of the second elastic body 150. Incidentally, in the present embodiment, the other end of the fifth link 162 and the other end of the second elastic body 150 are connected via a connecting member 180 arranged in the Z-axis direction. . The movement of the other end of the fifth link 162 in a direction other than the X-axis direction is restricted.

  The other end of the fourth link 161 is coupled to one end of the sixth link 163 so as to be rotatable about an axis parallel to the Y axis. The other end of the sixth link 163 is connected to one end of the third elastic body 164. Incidentally, in this embodiment, the other end of the sixth link 163 and one end of the third elastic body 164 are connected via a connecting member 190 arranged in the Z-axis direction. . The other end of the sixth link 163 is restrained from moving in directions other than the X-axis direction.

The third elastic body 164 is arranged in the X-axis direction. The other end of the third elastic body 164 is connected to the base 120. Here, the third elastic member 164 is set so as elastic force at a rotation angle phi ₃ is 0 ° state of the fourth link 161 is zero. The second elastic body 150 is set so that the elastic force becomes zero when the angle θ of the second link 112 is 0 ° and the rotation angle φ ₃ of the fourth link 161 is 0 °. ing.

  Such an initial elastic force introduction mechanism 160 is a second elastic body generated when an initial elastic force is introduced into the second elastic body 150 based on the same principle as the basic principle of the initial elastic force introduction mechanism shown in FIG. The restoring force of 150 and the force acting on the second elastic body 150 based on the elastic force of the third elastic body 164 function to cancel each other, so that the second elastic body 150 can be initially applied with a small force. Elastic force can be introduced.

  Moreover, the initial elastic force introduction mechanism 160 is housed in the base 120. Therefore, the operation of the first to third links is not hindered. Further, the lifting device 100 can be designed in a compact manner.

  Furthermore, since the first and second elastic bodies 140 and 150, which are heavy objects, are arranged on the base 120 side, a smaller force is sufficient when the initial elastic force is introduced into the second elastic body 150.

  The embodiment of the load compensation mechanism according to the present invention has been described above. However, the present invention is not limited to the above configuration, and can be changed without departing from the technical idea of the present invention. For example, in the above embodiment, the first action point P, the second action point A, and the third action point B are arranged at different positions, but they may be arranged at the same position. Thereby, the design process of a load compensation mechanism can be performed simply. In addition, the load compensation mechanism can be designed in a compact manner.

DESCRIPTION OF SYMBOLS 1 Link 2 1st elastic body 3 Base 4 Permissible part, 4a Protruding part, 4b Sliding plate 5 Second elastic body 6 Permissible part, 6a Protruding part, 6b Sliding plate 7 Initial elastic force introduction mechanism 8 3rd Elastic body 9 Link mechanism 9a, 9b Link 10 Restraining mechanism, 10a Linear guide, 10b Drive mechanism, 10c Sliding part, 10d Protruding part 11 Permissible part, 11a Protruding part, 11b Sliding plate 12, 13 Linear guide 14 Pulley 15 , 16 Linear guide 17 Link 18 First link, 18a First side, 18b Second side 19 Second link 20 Third link 21 First link 22 Second link 71 Initial elastic force introduction mechanism 72 Cam mechanism 73 cam body, 73a rotating shaft 74 restraint mechanism, 74a linear guide, 74b sliding portion, 74c protruding portion, 75 cam follower 91 link mechanism,
91a, 91b link 92 link mechanism, 92a first link, 92b second link, 92c third link 100 lifting device 110 link mechanism 111 first link, 111a roller 112 second link, 112a first side, 112b 2nd side, 112c roller 113 3rd link, 113a roller 120 base, 121 groove part 130 lifting / lowering base, 131 groove part 140 1st elastic body 150 2nd elastic body 160 initial elastic force introduction mechanism, 161 4th Link, 162 5th link, 163 6th link, 164 3rd elastic body 170 Luggage 180, 190 Connection member P 1st action point A 2nd action point B 3rd action point C 4th action Point D Fifth action point E Sixth action point F Seventh action point

Claims (5)

A first action point at which a load acts on the rotating body, a second action point at which the elastic force of the first elastic body acts on the rotating body, and an elastic force of the second elastic body acts on the rotating body. The third action point, and the rotation based on the torque around the rotation axis of the rotating body based on the load acting on the first action point and the elastic force acting on the second action point. A load compensation mechanism in which the resultant torque of the torque around the rotation axis of the rotating body acts in the opposite rotation direction and cancels out based on the torque around the rotation axis of the body and the elastic force acting on the third action point Because
An initial elastic force introduction mechanism for introducing an initial elastic force into the second elastic body ;
The initial elastic force introducing mechanism is:
A third elastic body;
A fourth action point that is an action point opposite to the third action point in the second elastic body;
A fifth action point at which the elastic force of the third elastic body acts;
A link mechanism connecting the fourth action point and the fifth action point;
A restraint mechanism for restraining movement of the second elastic body in a direction other than the expansion and contraction direction,
When an initial elastic force is introduced into the second elastic body, a restoring force generated in the second elastic body, and a force acting on the second elastic body based on the elastic force of the third elastic body; The load compensation mechanism that cancels out . The load compensation mechanism according to claim 1 , wherein an elastic coefficient of the second elastic body is equal to an elastic coefficient of the third elastic body. The load compensation mechanism according to claim 1 or 2 , wherein the second elastic body and the third elastic body are arranged in parallel. The load compensation mechanism according to claim 1 or 2 , wherein the second elastic body and the third elastic body are disposed so as to be orthogonal to each other. A first action point at which a load acts on the rotating body, a second action point at which the elastic force of the first elastic body acts on the rotating body, and an elastic force of the second elastic body acts on the rotating body. The third action point, and the rotation based on the torque around the rotation axis of the rotating body based on the load acting on the first action point and the elastic force acting on the second action point. A load compensation mechanism in which the resultant torque of the torque around the rotation axis of the rotating body acts in the opposite rotation direction and cancels out based on the torque around the rotation axis of the body and the elastic force acting on the third action point Because
An initial elastic force introduction mechanism for introducing an initial elastic force into the second elastic body;
The initial elastic force introducing mechanism is:
A fourth action point that is an action point opposite to the third action point in the second elastic body;
A cam mechanism for transmitting a driving force to the fourth operating point;
A restraint mechanism for restraining movement of the second elastic body in a direction other than the expansion and contraction direction,
A load compensation mechanism in which a cam shape of the cam body is set so that a torque generated in the cam body by a restoring force of the second elastic body becomes constant when the cam body of the cam mechanism rotates.

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