JPH0554762A - Breaker - Google Patents

Abstract

PURPOSE:To prevent a reduction in torque at the time of opening and hold stable torque characteristic. CONSTITUTION:A driving shaft 1 has a driving lever 30 and a projection 31, and pins 32 are mounted in three positions on the projection 31. An arm driving cam 33 having the same rotating shaft as the driving shaft 1 and made mutually rotatable has projections 34 in three positions on the inner circumferential side, and pins 35 are mounted on the projections 34 in correspondence to the pins 32. Compression springs 36 are mounted between the respective corresponding pins 32 and 35. A movable contact 13 connecting/disconnecting with a fixed contact 15 is connected to the driving lever 30 through links 8, 9, a driving lever 10, and a contact driving part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker, and more particularly to improvement of its operating mechanism.

[0002]

2. Description of the Related Art FIG. 11 shows an example of a conventional circuit breaker. In the figure, the drive shaft 1 is pivotally attached to a frame (not shown), has the same rotary shaft as the drive cam 2, and is rotatable with respect to each other. A spiral spring 3 having one end fixed to the drive shaft 1 and the other end fixed to the drive cam 2 is provided between the drive shaft 1 and the drive cam 2. A drive lever 4 is fixed to the drive shaft 1, and a tip 4a of the drive lever 4 is arranged so that it can be engaged with a half-moon shaped cross section of the trip shaft 5. Trip shaft 5
Can be rotated by the trip lever 7 driven by the trip coil 6, and the tip 4a of the drive lever 4 and the half-moon shaped cross section of the trip shaft 5 can be disengaged.
A contact drive lever 10 is connected to the drive lever 4 via a link 8 and a link 9. The contact drive lever 10 is a shaft
It can be rotated by 11. The contact drive lever 10 and the movable contact 13 are integrated with the movable contact 13 via the elliptical hole 12a.
And a contact pressure spring 14 are attached. The contact drive unit 12 is provided with an insulating joint (not shown) in the middle.
An insulator (not shown) is provided between the contact pressure spring 14 and the contact drive lever 10. 15 is a fixed contact.

The links 8 and 9 have links.
16 are connected, and the other end of the link 16 is connected to the drive cam 2.
The drive cam 2 is provided with a claw 2a that engages with the half-moon shaped cross section of the closing shaft 17, and when the closing coil 17 rotates the closing shaft 17, the engagement between the closing shaft 17 and the claw 2a can be released. Reference numeral 19 is a stopper of the drive cam 2, and 20 is a stopper of the contact drive lever 10.

FIG. 11 shows the released state of the spiral spring 3. However, a spring energy storage mechanism (not shown) (for example, a cam driven by a motor is engaged with a roller 2b provided on the drive cam 2) is used. When the drive cam 2 is rotated counterclockwise in the figure, a spring energy storage state is established as shown in FIG. At this time, the closing shaft 17 is rotated counterclockwise by a spring (not shown), and its half-moon shaped cross section engages with the claw 2a. Further, when the drive cam 2 rotates counterclockwise, the link 16 drives the nodes of the link 8 and the link 9 to the right in the figure, and the drive lever 4 is pushed downward in the figure. At this time, the trip shaft 5 is rotated clockwise by a spring (not shown), and its half-moon-shaped cross section engages with the tip 4a of the drive lever 4. When the driving force is released in this state, it enters a standby state as shown in FIG.

When the closing shaft 17 is rotated clockwise by the closing coil 18 or a closing button (not shown) in the state shown in FIG. 12, the engagement between the claw 2a and the half-moon shaped cross section of the closing shaft 17 is released, and the driving is performed. The cam 2 is driven by the spiral spring 3 to rotate clockwise, and is in a closed state as shown in FIG.

In the state shown in FIG. 13, when the trip shaft 5 is rotated counterclockwise by the trip coil 6 or a trip button (not shown), the tip 4a of the drive lever 4 is rotated.
Is disengaged from the half-moon shaped cross-section of the trip shaft 5, and the drive lever 4 is driven by the spiral spring 3 to rotate counterclockwise, and the contact is opened as shown in FIG.

[0007]

However, in the circuit breaker configured as described above, the spiral spring 3 is used as the drive shaft 1.
Is proportional to the rotation angle of the drive shaft 1 as shown in FIG. Therefore, the characteristics of this spiral spring are
The torque is the largest in the 12 stored states, the closed state in Fig. 13,
The torque decreases as the contact opens in Fig. 11. Such characteristics are sufficient for a circuit breaker with a small breaking capacity, but have a large breaking capacity, a high opening speed,
With a circuit breaker that requires a large opening force, the torque during opening may be insufficient.

Therefore, an object of the present invention is to provide a circuit breaker provided with an operating mechanism having a stable torque characteristic in which the torque at opening is not reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has a drive shaft to which a drive force is applied by a spring, and a pair is provided via a link mechanism connected to the drive shaft and a contact drive unit connected to the link mechanism. A circuit breaker that opens and closes the contact of, has a first fulcrum provided on the drive shaft and a rotation shaft that is the same as the drive shaft,
Further, the drive shaft is rotatable with respect to each other, a second fulcrum provided on the rotary body such that the distance from the drive shaft is larger than the first fulcrum, the first fulcrum and the second fulcrum. It is composed of a compression spring mounted between the fulcrum and.

[0010]

The torque T applied to the drive shaft by the compression spring is such that the force of the compression spring is P and the angle between the direction of the force of the compression spring and the straight line passing through the first fulcrum and the axis of the drive shaft is as shown in FIG. To θ ₁
Then, it is given by T = P × L ₁ × Sin θ ₁ . Here, L ₁ is the first from the axis of the drive shaft.
It is the distance to the fulcrum of. Moreover, the force P of the compression spring, the free length of the compression spring L _0, if the operating time length is L _2, is given by _{P = K × (L 0 -L} 2). Here, K is the spring constant of the compression spring, and the operating length L ₂ is the angle θ between the first fulcrum and the second fulcrum with respect to the shaft center of the drive shaft, and the second from the shaft center of the drive shaft. The distance to the fulcrum is L ₃ , and the diameters of the first fulcrum and the second fulcrum are d.
Then, it is given by the following formula.

[0011]

[Equation 1]

General torque T given by these equations
The relationship between the angle and the angle θ is illustrated in FIG. As is clear from the figure, the characteristic of the driving force can be made stable with a small influence of the angle θ within a certain angle range.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a drive shaft, and a drive lever 30 is integrally provided. The drive lever 30 is arranged such that the tip 30a can engage with the half-moon shaped cross-section of the trip shaft 5 and is provided with a protrusion 31.
Install them evenly in the places. Further, the drive cam 33, which is shared by the drive shaft 1 and the rotary shaft and is rotatable with respect to each other, has projections 34 equidistantly provided at three locations on the inner periphery thereof, corresponding to the pins 32, respectively. Attach 35 and put shaft 17 on the outer circumference
A claw 33a that engages with the half-moon shaped cross section and a roller 33b that engages with a spring accumulating mechanism (not shown) are provided. Compression spring 36
Are attached at three points with the pins 32 and 35 facing each other as fulcrums.

Therefore, the drive cam 33 has a structure as shown in FIGS.
As shown in FIG. 3, a protrusion 33c having an arm shape and provided on the bottom is rotatably supported by a support plate 38 attached to a frame body 37 of the circuit breaker. The drive shaft 1 has one end (right side in FIG. 3) 1a rotatably supported by the frame 37, and the other end 1a.
b is rotatably supported by the protruding portion 33c of the drive cam 33. On the other hand, the compression spring 36 has a force such that the torque T in the released state of the movable contact 13 keeps the opened state of the movable contact 13, and as shown in FIG. The free length L ₀ of the compression spring 36 and the positions of the pins 32 and 35 are set so that the torque T for driving the drive cam 33 in the clockwise direction in the same figure is applied in the state where energy is stored. FIG. 4 shows the relationship between the torque T and the rotation angle θ, and the relationship between the energy storage state, the closing state, and the opening state. The other configurations are the same as the conventional configurations shown in FIGS. 11 to 13.

Next, the operation of the embodiment configured as described above will be described. 3 shows the compression spring 36 in the released state,
When the drive cam 33 is rotated counterclockwise in the figure by a spring-accumulation mechanism (not shown), the spring-accumulated state is established as shown in FIG. At this time, the closing shaft 17 is rotated counterclockwise by a spring (not shown), and its half-moon shaped cross section engages with the claw 33a. Further, by the counterclockwise rotation of the drive cam 33, the link 16 drives the nodes of the link 8 and the link 9 to the right in the figure, and pushes the drive lever 30 downward in the figure.
At this time, the trip shaft 5 is rotated clockwise by a spring (not shown), and the half-moon shaped cross section of the trip shaft 5 is engaged with the tip 30a of the drive lever 30. When the driving force is released in this state, it enters a standby state as shown in FIG.

In the state shown in FIG. 7, when the closing coil 17 or the closing button (not shown) is used to rotate the closing shaft 17 in the clockwise direction, the engagement between the claw 30a and the half-moon shaped cross section of the closing shaft 17 is released, and the driving is performed. The cam 33 is driven by the compression spring 36 to rotate in the clockwise direction, and enters the closed state as shown in FIG. In the state shown in FIG. 8, when the trip shaft 5 is rotated counterclockwise by the trip coil 6 or a trip button (not shown), the engagement between the tip 33a of the drive cam 33 and the half-moon shaped cross section of the trip shaft 5 is released. The drive lever 30 is driven by the compression spring 36 to rotate counterclockwise, and the contact is opened as shown in FIG.

By the way, according to the above-mentioned structure, as shown in FIG. 6, the torque T is relatively small at the initial stage when the load of the drive shaft 1 is small and the load state is changed to the closing state. The compression spring 36 and the pins 32, 35 are configured so that the torque T becomes maximum immediately before the closing state in which the load acts and the load becomes large. Further, in order to increase the initial opening speed that greatly affects the breaking performance of the circuit breaker, The compression spring 36 and the pins 32, 35 can be configured such that the torque T is large at the initial stage of the opening operation and only the opening holding force is required to be small in the opening state.

Therefore, according to the embodiment constructed as described above, a necessary and sufficient torque can be applied to the drive shaft when necessary, so that the operating mechanism with good energy efficiency of the spring can be constructed with a simple structure. Obtainable. Further, since the energy efficiency of the spring is good, the spring can be downsized, and the circuit breaker can be downsized and lightweight. Furthermore, by arranging a plurality of compression springs in axial symmetry with respect to the drive shaft, the force vectors of the compression springs cancel each other out in the drive shaft direction, and only the force vector component in the torque acting direction remains. The friction of the bearing portion of the drive shaft is reduced, and the efficiency of the drive force of the spring is improved.

The present invention is based on the above-mentioned embodiment (hereinafter,
It is not limited to the first embodiment), and various modifications can be made. FIG. 9 shows another embodiment of the present invention (hereinafter referred to as a second embodiment). In the figure, a projection 31 is provided on the drive shaft 1, and a pin 32 is attached as a fulcrum of a compression spring 36. In addition, a protrusion 34 provided on a drive cam 33 that shares a rotary shaft with the drive shaft 1 and is rotatable relative to each other.
A pin 35 is attached as a fulcrum to the other end of the compression spring 36. This configuration is the same as in FIG. The drive shaft 1 has
Further, cam plates 40 and 41 are fixedly provided. Cam plate
Cam grooves 40a and 41a are respectively provided in the 40 and 41 so as to face each other, and a pin 42 that engages with the cam grooves 40a and 41a is mounted between the cam plates 40 and 41. Pin 42 has a fulcrum shaft
The other end of the link 44, one end of which is rotatably supported by 43, is rotatably connected, and the one end is further connected to the contact drive lever 10.
The other end of the link 9 connected to is rotatably connected.

The cam plates 40 and 41 have projections 40b and 41b.
Is provided, and the projection 40b is engaged with the closing catch 45,
The trip catch 46 is engaged with 41b. The closing catch 45 and the trip catch 46 are respectively the closing shaft 17,
The trip shaft 5 is engaged at the half-moon-shaped cross section and driven by a closing coil, a trip coil or a closing button or a trip button (not shown), and the engagement is released. Further, the unevenness of the cam grooves 40a and 41a is different from the projection 40b.
The contact drive lever 10 is in the open position when the protrusion 40b is engaged with the closing catch 45, and the contact drive is performed when the protrusion 41b is engaged with the trip catch 46. The lever 10 is formed so as to be in the closing position. In addition, the contact drive unit 12, the movable contact 13,
The contact pressure spring 14 and the fixed contact 15 are not shown.

FIG. 10 shows the relationship between the torque T of the drive shaft 1 and the rotation angle θ in this second embodiment, and the relationship between the closed and open states. In the figure, the closed state (1) is called the fully charged state, and the open state (2) is called the completely released state. The operation of the second embodiment having the above construction will be described with reference to FIGS. 9 and 10. First, the drive cam 33 is rotated by a spring energy storage mechanism (not shown) from the completely released state, that is, the open state (2). It moves to store the compression spring 36 in the open state (1). Next, the closing shaft 17 is driven to be in the closing state (2). At the same time, the drive cam 33 is rotated by the spring energy storage mechanism to store energy up to the closed state (1), that is, the complete energy storage state. Here, when the trip command is given, the contact is opened (1). Further, when the closing command is given here, the closing state (2) is set, and at the same time, the drive cam 33 is rotated by the spring energy storing mechanism to store the state in the closing state (1), that is, in the completely stored state. Normally, the cycle from this closed state (1) to the open state (1), the closed state (2), and then the closed state (1) is repeated, but in the case of high-speed reclosing, the closed state (1)
When the contact state is changed to the open state (1), the state immediately changes to the closed state (2), and the trip command is given before the spring energy storage mechanism operates to enter the open state (2), that is, the completely released state. ..

Therefore, according to the second embodiment described above, the torque T is relatively small at the initial stage of the transition from the energy storage position where the load on the drive shaft 1 is small to the closing state, as in the first embodiment described above. The contact pressure spring 14 operates, and the compression spring 36 and the pins 32 and 35 are configured so that the torque T becomes maximum immediately before the closing state in which the load increases, and the initial opening that greatly affects the breaking performance of the circuit breaker. In order to increase the separation speed, the torque T is large at the initial stage of the opening operation, and it is sufficient to have only the opening holding force.
And pins 32 and 35 can be configured. As a result, the duty of high-speed reclosing can be executed, and the application of the circuit breaker can be expanded as compared with the first embodiment. Further, in the second embodiment, as in the first embodiment, a necessary and sufficient torque can be applied to the drive shaft when necessary, so that an operating mechanism with good energy efficiency of the spring can be obtained with a simple configuration. In addition, the driving cam does not reverse in one direction, so that the structure of the energy storage mechanism can be simplified.

[0023]

As described above, according to the present invention, the torque is relatively small at the initial stage when the load of the drive shaft is small and the load is changed to the closing state, and the contact pressure spring operates.
It is possible to obtain the characteristics of the operating mechanism that maximize the torque immediately before the load is closed, and to increase the initial opening speed that greatly affects the breaking performance of the circuit breaker. The operating mechanism has a stable torque characteristic in which the torque at opening is small and the torque at opening is small. Can be provided.

Further, since the characteristic feature of the spiral spring that the closing spring and the opening spring can be used together can be realized by the compression spring, it is not necessary for the closing spring to store the opening spring at the time of closing, and the conventional opening spring can be used. The throwing force can be reduced as compared with a circuit breaker provided with a closing spring, respectively, which enables downsizing of the spring and reduction in size and weight of the circuit breaker as a whole.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of the present invention.

FIG. 2 is a torque characteristic diagram of a main part of the present invention.

FIG. 3 is a configuration diagram of an embodiment of the present invention.

FIG. 4 is a front view showing a part of a main part of an embodiment of the present invention.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a torque characteristic diagram of an embodiment of the present invention.

FIG. 7 is an explanatory view of the operation of one embodiment of the present invention.

FIG. 8 is an explanatory view of an operation different from that of FIG. 7 of the embodiment of the present invention.

FIG. 9 is a perspective view showing a main part of another embodiment of the present invention.

FIG. 10 is a torque characteristic diagram of another embodiment of the present invention.

FIG. 11 is a configuration diagram of a main part of a conventional circuit breaker.

FIG. 12 is an explanatory view of the operation of the conventional circuit breaker.

FIG. 13 is an explanatory view of the operation of the conventional circuit breaker different from that of FIG.

FIG. 14 is a torque characteristic diagram of a spiral spring of a conventional circuit breaker.

[Explanation of symbols]

1 ... Drive shaft, 5 ... Trip shaft, 8, 9, 16 ... Link, 10 ... Contact drive lever, 12 ... Contact drive part, 13 ... Movable contact, 14 ... Contact pressure spring, 15 ... Fixed contact, 17 ... Shaft, 30 ... Drive lever, 31 ... Protrusion, 32, 35 ... Pin, 33 ... Drive cam, 36 ... Compression spring, 37 ... Frame body.

Claims (1)

[Claims] 1. A circuit breaker having a drive shaft to which a driving force is applied by a spring, and opening and closing a pair of contacts via a link mechanism connected to the drive shaft and a contact drive unit connected to the link mechanism. A rotary body having a first fulcrum provided on the drive shaft, the same rotary shaft as the drive shaft, and the drive shaft being rotatable relative to each other; A circuit breaker characterized by comprising a second fulcrum provided so as to increase the distance from the drive shaft, and a compression spring mounted between the first fulcrum and the second fulcrum. ..