JPS6344580Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an overload prevention device interposed between two rotating transmission shafts.

An overload prevention device prevents an accident by canceling power transmission between an input shaft and an output shaft when an abnormal overload occurs in a power transmission system. In conventional devices of this type, for example, as shown in Utility Model Publication No. 43-13536, Utility Model Application Publication No. 54-546, etc., a movable meshing part of one shaft is connected to a meshing part of the other shaft. Since the structure is simply biased and supported by a spring or the like so that it can be freely engaged and disengaged, when an overload occurs, the movable engaging part normally engages and disengages violently from the engaged part repeatedly at short intervals. There were problems with impact damage and significant impact noise.

The purpose of the present invention is to solve the above-mentioned problems with conventional devices by gently returning the movable meshing part to the meshed part, and to avoid damage to the power transmission system due to impact and generation of severe noise. The object of the present invention is to provide an overload prevention device that can maintain stable performance.

The overload prevention device of the present invention, which achieves the above object, is an overload prevention device in which a connection part is provided between an input shaft and an output shaft to cancel power transmission due to overload. A movable meshing part provided on the distal end side of the other shaft rotatably fitted into the cylindrical case is detachably connected to the mating part, and the cylindrical case is connected to the other shaft part at the end. A sealed chamber is formed by sealing with a sealed lid plate,
In addition to sealing oil in the sealed chamber, the volume of the sealed chamber divided into the meshing side and the non-meshing side is made variable by a sliding press plate on the other shaft, and the volume of the sealed chamber on the non-meshing side is made variable. While a biasing spring is provided to normally press the above-mentioned pressing plate toward the engaged part, the pressing plate has an oil flow port with a check valve to the meshing side sealed chamber, and an oil flow path with a smaller flow area than this oil flow port. When the meshing part on the output shaft side resists the urging spring due to overload and releases the coupling with the meshing part on the input shaft side, the pressing plate prevents the movable meshing part from returning to the meshing position. It is characterized by being configured to provide a slow-slow buffer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments shown in the drawings.

The figures show an overload prevention device according to an embodiment of the present invention. Fig. 1 is a longitudinal cross-sectional view when power is being transmitted between two rotary transmission shafts, and Fig. 2 is a longitudinal sectional view when power transmission is in a released state. It is a longitudinal cross-sectional view in a certain case.

In the figure, 1 is a power input shaft, and 2 is an output shaft. The end of the output shaft 2 is formed in a cylindrical case 2a, and a plurality of cylindrical grooves 3 are bored in the bottom surface of the cylindrical case 2a. on the other hand,
A disc-shaped flange 1a is provided at the end of the input shaft 1, and this flange 1a is rotatably fitted into the cylindrical case 2a of the output shaft 2. Guide holes 4 are formed in the flange 1a at positions corresponding to the grooves 3 so as to pass through them in the front and back, and steel balls 5 are slidably fitted into the guide holes 4, respectively. There is.

A press plate 6 is provided at the rear of the flange 1a, and is slidably mounted on the input shaft 1. Ball 5 touched by 7
An elastic force is applied toward the side. Reference numeral 8 denotes a lid plate that closes the open end of the cylindrical case 2a, and serves to provide a sealed structure inside the cylindrical case 2a and to fix the disc spring 7. The cover plate 8 is fixed by a retaining ring 9, and an oil seal 10 is installed between the cover plate 8 and the input shaft 1. The cylindrical case 2a, which is thus closed by the lid plate 8, is filled with oil.

A press plate 6 slidably mounted on the input shaft 1
The inside of the cylindrical case 2a is divided into sealed chambers 11a and 11b, which are divided into a meshing side and a non-meshing side. The press plate 6 has a small diameter oil flow port 1 penetrating into the sealed chambers 11a and 11b at its radially intermediate portion.
2 and an oil flow port 13 on its outer periphery.
In addition, a sealed chamber 1 is provided in the oil flow port 13.
A check valve 14 is provided that allows oil to flow from 1b to 11a but prevents oil from flowing from sealed chamber 11a to 11b. In addition, oil flow port 12
has a small diameter, and its flow path area is equal to the oil flow port 1.
It is set to be significantly smaller than that of No. 3. Reference numeral 15 denotes an O-ring, which seals the fitting portion of the press plate 6 with the input shaft 1.

In the above-mentioned device, when no abnormal overload occurs, the ball 5, which is the movable meshing part, presses against the groove 3, which is the meshing part, through the press plate 6, as shown in FIG. They are biased by the elastic force of the disk spring 7 into a meshed state, so that the power of the input shaft 1 is smoothly transmitted to the output shaft 2.

Now, if an overload occurs here, the ball 5 receives a large thrust from the outer peripheral wall of the groove 3 and
This component force overcomes the elastic force of the disk spring 7 and causes the ball 5 (movable meshing part) and the groove 3 (meshing part) to move as shown in FIG. The meshing state of the input shaft 1 is released, and the power of the input shaft 1 is no longer transmitted to the output shaft 2. At this time, the third
As shown in the figure, as the pressing plate 6 is pushed by the ball 5 and moves to the right side in the figure, the oil on the side of the sealed chamber 11b presses the check valve 14 and flows from the oil flow port 13 to the sealed chamber 11a on the meshing side. There will be an influx. The sealed chamber 11
Since the oil entering the a side is blocked by the check valve 14, it flows from the oil flow port 13 into the sealed chamber 11b on the non-meshing side.
It cannot flow out to the side, and there is a small oil flow port 1.
It can only flow from 2. Therefore, the volume of the sealed chamber 11a changes slowly, and the pressure plate 6 is held by the oil and cannot return to the flange 1a side suddenly, and the oil flow port 1
It will slowly return to its original position depending on the amount of oil flowing out from 2. Therefore, no impact occurs when the ball 5 of the movable meshing part engages with the groove 3 of the meshed part again, and therefore, there is no damage or generation of severe noise unlike in the conventional case.

In addition, in the above-mentioned device, the power connection portion is connected to the guide hole 4.
Since the structure is based on the engagement between the ball 5 that slides on the groove 3 and the groove 3, the sliding resistance between the two during engagement and disengagement is small, and an initial break-in operation is required unlike the conventional engagement structure using splines, etc. It will no longer be.

In the above embodiment, the oil flow port 13 on the pressure plate 6 provided to partition the sealed chamber 11a is provided on the outer periphery of the pressure plate 6, but the flow path area is made larger than that of the oil flow port 12. If you configure it so that
The space between the outer periphery of the pressing plate 6 and the inner periphery of the cylindrical case 2a may be oil-tight and slidable, and may be provided at the intermediate portion of the pressing plate 6. A check valve 14 for the oil flow port 13 must be provided.

As mentioned above, the present invention provides an overload prevention device in which a connecting part is provided between an input shaft and an output shaft to cancel power transmission due to overload, and the present invention provides an overload prevention device in which a connecting part is provided between an input shaft and an output shaft to cancel power transmission due to overload. The movable meshing part provided on the tip side of the other shaft rotatably fitted into the cylindrical case can be freely engaged and detached, and the cylindrical case is attached to a lid plate that seals the other shaft part at the end. to form a sealed chamber, seal oil in the sealed chamber, and change the volume of the sealed chamber divided into a meshing side and a non-meshing side by a sliding press plate on the other shaft. None, and a biasing spring is provided in the sealed chamber on the non-meshing side to normally press the above-mentioned pressing plate toward the meshed part, while the pressing plate has an oil flow port with a check valve to the sealed chamber on the meshing side and an oil outlet for this oil. When the engagement part on the output shaft side resists the energizing spring and releases the connection with the engagement part on the input shaft side due to overload, the above-mentioned Since the pressure plate is configured to provide a slow-slow buffer for the return engagement of the movable meshing part, the sealed chamber that expands in response to the overload together with the movable meshing part is held by oil and slowly shrinks, causing the movable meshing part to move. It will return to the original engaged part,
It is possible to prevent the generation of impact when engaging again. Therefore, damage caused by impact and generation of noise can be prevented.

In addition, when the meshing part is configured with a ball guided by a guide hole and a groove, the initial sliding resistance can be made small from the beginning, as in meshing with splines, etc. It can eliminate the need to drive.

[Brief explanation of the drawing]

The figures show an overload prevention device according to an embodiment of the present invention. Fig. 1 is a longitudinal cross-sectional view when power is being transmitted between two rotating transmission shafts, and Fig. 2 is a longitudinal cross-sectional view when power is being transmitted during overload. Longitudinal cross-sectional view in the released state,
FIG. 3 is a longitudinal cross-sectional view of the main parts when the power transmission is in the released state. 1... Input shaft, 1a... Flange, 2... Output shaft, 2a... Cylindrical case, 3... Concave groove (meshing part), 4... Guide hole, 5... Ball (movable meshing part), 6...Press plate, 7...Disc spring, 8...Lid plate,
11a, 11b... sealed chamber, 12, 13... oil flow port, 14... check valve.

Claims (1)

[Scope of utility model registration request] In an overload prevention device that has a connecting part that cancels power transmission due to overload between the input shaft and the output shaft, the shaft can be rotated freely within the cylindrical case with respect to the engaged part of the shaft that is integrated with the cylindrical case. The movable meshing part provided on the tip side of the other shaft inserted into the housing is made freely engageable and detachable, and the cylindrical case is sealed at the end with a cover plate that seals the other shaft portion to form a sealed chamber. death,
In addition to sealing oil in the sealed chamber, the volume of the sealed chamber divided into the meshing side and the non-meshing side is made variable by a sliding press plate on the other shaft, and the volume of the sealed chamber on the non-meshing side is made variable. While a biasing spring is provided to normally press the above-mentioned pressing plate toward the engaged part, the pressing plate has an oil flow port with a check valve to the meshing side sealed chamber, and an oil flow path with a smaller flow area than this oil flow port. When the meshing part on the output shaft side resists the urging spring due to overload and releases the coupling with the meshing part on the input shaft side, the pressing plate prevents the movable meshing part from returning to the meshing position. An overload prevention device characterized by being configured to provide slow and slow buffering.