JPH04145207A - Friction clamping device - Google Patents

Abstract

PURPOSE:To attain positive fastening and expedite action by providing annular oil chambers between the inside of outer cylinders and the outer diameter parts of sleeves forming clamp units, and fastening a rod and the outer cylinders through collared sleeves at the time of oil pressure acting upon the annular oil chambers. CONSTITUTION:Clamp units 38a-38c are disposed in the axially overlapped state at the periphery of a rod 10. The clamp units 38a-38c are respectively formed of outer cylinders 12a-12c and collared sleeves 14a-14c with a rod 10 inserted through, and annular oil chambers 22a-22c sealed by seal material 30 and communicated with oil passages 24a-24c are formed between the outer cylinders 12a-12c and the sleeves 14a-14c. The lower stage collared sleeves 14a, 14b are respectively fitted to the upper stage outer cylinders 12b, 12c, and the respective collared sleeves 14a-14c clamp the rod 10 at the inner diameter parts thereof by the lead-in of oil pressure to the annular oil chambers 22a-22c. The cycle time at the time of small load is thereby shortened, and cost reduction and durability are improved.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a friction type clamp device.

(B) Conventional technology As shown in FIG. 5, there is a friction type clamping device in which a rod 100 and a flange sleeve 110 are connected or released by hydraulic pressure. Hydraulic pressure is supplied to the flange sleeve 110 and the outer cylinder 120 fitted thereto.
The oil is supplied to an annular oil chamber 130 formed between the oil and oil via an oil passage 140 that communicates with the annular oil chamber 130 . For example, rod 100
The inner diameter of the flanged sleeve 110 is fitted to the outer diameter of the flanged sleeve 110 so that they can move in the axial direction when no external force is applied, and when it is necessary to fasten the two, hydraulic pressure is applied from the outer diameter of the flanged sleeve 110. is applied to elastically deform the flanged sleeve 110 in the radial direction, and the two are fastened together by frictional force. In addition, the flange sleeve 110 and the outer cylinder 12
Seal members 150 are provided above and below between the annular oil chamber 130 and the annular oil chamber 130 to keep it oil-tight.

(C) Problems to be Solved by the Invention However, in the conventional friction type clamp device as described above, when the rod 100 and the outer cylinder 120 are fastened together, the annular oil chamber 130 is always closed regardless of the magnitude of the load. Because hydraulic oil is supplied throughout the device, it takes a relatively long time for the friction type clamp device to go from a released state to a fastened state. In addition, the overall length of the sleeve 110 is long, and when a load is applied, the sleeve 110 expands greatly, resulting in increased relative slippage with the rod 100 (thus increasing wear).

In addition, in order to securely connect the rod 100 and the inner diameter of the flanged sleeve 110, the dimension of the gap between the rod 100 and the inner diameter of the flanged sleeve 110 must be strictly controlled. It is difficult to process the inner diameter with precision. In addition, when increasing the clamping capacity, the sleeve 11
Although the total length of the sleeve 110 is increased, the thickness of the sleeve 110 must also be increased accordingly, resulting in an inefficient clamping device.

The present invention aims to solve such problems.

(d) Means for Solving the Problems The present invention provides a plurality of clamp units superimposed on the outer periphery of a rod, and each clamp unit is made up of an outer cylinder and a sleeve with a flange fitted onto the inner diameter of the outer cylinder. By configuring this, the above problem is solved. That is, the friction type clamp device of the present invention includes a rod (10) and a plurality of clamp units (38a, 38b-38c) provided on the outer periphery of the rod (10) to overlap each other in the axial direction. The clamp unit (38) includes an outer cylinder (12),
The rod (10) is fitted into the inner diameter of the rod (10).
and a flange sleeve (14) fitted together so as to be relatively movable in the axial direction. an annular oil chamber (22) is formed between the inner diameter of the outer cylinder (12) and the outer diameter of the collared sleeve (14); The fit between the rod (10) and the inner diameter part of the flange sleeve (14) is such that when no hydraulic pressure is applied to the annular oil chamber (22), the rod (10) and the outer cylinder (12) are aligned in the axial direction. The rod (10) and the outer cylinder (12) are configured to be in a fastened state via the collared sleeve (14) when the rod (10) and the outer cylinder (12) are movable relative to each other and when hydraulic pressure is applied to the annular oil chamber (22). ing.

In addition, the rod (10) and clamp unit (38a/
38b, 38c) is provided with a load sensor (28) for detecting the load, and a clamp unit (38a, 38b, 38c) is selected according to the magnitude of the signal and hydraulic pressure is supplied to it. A controller (42) that outputs a signal may be provided.

Further, a fixed platen (16) fitted to the clamp unit (78a) located at the distal end in the direction of load application is provided, and the fixed platen (16) is connected to the clamp unit (78a) at the distal end.
), and is fitted with the rod (10) so as to be movable relative to it in the axial direction; ) and the outer periphery of the rod (10) form a load support oil chamber (26), and a pressure sensor (29) detects the pressure acting on the load support oil chamber (26). , and a controller (42) that outputs a signal to select the clamp unit (78a, 78b, 78c) and supply hydraulic pressure to the clamp unit (78a, 78b, 78c) according to the magnitude of the signal.

In addition, a movable platen (56) fitted to the clamp unit (78a) located at the end in the direction of load application is provided, and one end of the rod [50] is fixed to a fixed part, and the movable platen ( 56) includes a clamp unit (78a) at the distal end.
) and can move relative to the rod (5) in the axial direction.
0) and is movable relative to this in the axial direction, and the clamp unit (
A load supporting oil chamber (66) is formed by the distal end of the rod (78a) and the outer periphery of the rod (50), and the clamp unit (78
A, 78b, 78c) may be selected and a controller (76) may be provided that outputs a signal to supply hydraulic pressure to the selected one. Note that the symbols in parentheses indicate corresponding members in the embodiment.

(E) When no hydraulic pressure is applied to the operating annular oil chamber, 1. The rod and the clamp unit are relatively free to move in the axial direction. When hydraulic pressure is applied to the annular oil chamber, the flanged sleeve is elastically deformed in the radial direction, and its inner diameter is pressed against the outer diameter of the rod. This causes the clamp unit to clamp the rod. That is, the friction type clamp device is in a fastened state. When a light load is applied, one of the multiple clamp units can be brought into a fastened state by supplying hydraulic pressure, so the cycle time is shorter than when supporting with a single long clamp unit. In addition, the energy required for fastening can be reduced. Furthermore, since the thin inner diameter cylindrical portion of the flanged sleeve can be shortened in size, processing becomes simple and the device can be made inexpensive.

(F) Example (First Example) FIG. 1 shows a first example of the present invention. cylindrical rod 1
Three clamp units 38a, 38b, 3 on the outer circumference of 0
8c are arranged in an overlapping state in the axial direction.

Since the clamp units 38a, 38b, and 38c are all similar, they will be described as the clamp unit 38 unless it is necessary to specify them. The clamp unit 38 is composed of a cylindrical outer cylinder 12 and a sleeve 14 fitted with the sleeve and movable in the axial direction.
In the figure, it is fitted onto the rod IO with the top facing up. The flange sleeve 14 is capable of transmitting a downward load W in the figure acting on the rod 10 to the outer cylinder 12 via the flange 18. The outer cylinder 12 has a cylindrical recess formed in the middle part of the inner diameter part in the longitudinal direction, and an annular oil chamber 22 is formed by this and the outer diameter part of the collared sleeve 14 . An oil passage 24 is formed in the outer cylinder 12 and communicates with the annular oil chamber 22 from the outer surface thereof. In response to a command signal from a controller 42, which will be described later, hydraulic pressure can be supplied to the annular oil chamber 22 from a clamp hydraulic circuit (not shown) through the oil passage 24. Rod 10 and collared sleeve 1
4, the rod 10 and the clamp unit 38 are movable relative to each other in the axial direction when no hydraulic pressure is applied to the annular oil chamber 22, and when no hydraulic pressure is applied to the annular oil chamber 22. If so, the relevant dimensions are set such that the clamping unit 38 clamps the rod 10. Seal members 30 are installed at the upper and lower positions of the annular oil chamber 22 in the figure.
are provided for each. The seal member 30 can prevent oil leakage from the annular oil chamber 22. In the figure, the outer diameter portion of the flange 18a of the lower flange sleeve 14a is fitted into the large diameter hole 20b of the middle outer cylinder 12. Similarly, the flange 1 of the middle flange sleeve 14b
The outer diameter portion of 8b is fitted into the large diameter hole 20c of the upper outer cylinder 12c. The outer diameter portion of the flange 18c of the upper flange sleeve 14c is open with no mating member to be fitted thereto. Clamp units 38a, 38b, 3
The flange sleeves 14a, 14b, and 14c of 8c have different axial lengths, and correspondingly, the annular oil chambers 22a, 22b, and 22c have different axial lengths. That is, the lower clamp unit 38a in the figure has the longest clamp portion, the middle clamp unit 38b has an intermediate length, and the lower clamp unit 38c has the shortest length. . As a result, the ratio of the maximum load that can be clamped, for example, of the clamp unit 38a is
4'', the clamp unit 38b is set to ``2'', and the clamp unit 38c is set to rLJ.

A load sensor (load cell) 28 is fixed to the lower end of the outer periphery of the outer cylinder 12a at the lower stage in the figure. The load sensor 28 is capable of measuring the downward load -W in the figure that is transmitted from the rod 10 to the outer cylinder 12a when the clamp unit 38 is in a clamped state. Load sensor 28
A comparator 40 is connected to the controller 42 .
is connected. Two preset loads can be set in the comparator 40 in advance. The comparator 40 is
It is possible to compare the output from the load cell 28 with these set values and output a signal according to the result to the controller 42. The controller 42 determines to supply hydraulic pressure to one or more of the three clamp units 38a, 38b, and 38c according to the signal from the comparator 40, and supplies hydraulic pressure to a clamp hydraulic circuit (not shown). It is possible to direct the supply.

Next, the operation of this first embodiment will be explained. When oil pressure is not acting on the annular oil chamber 22, no external force is acting between the inner diameter of the collared sleeve 14 and the outer diameter of the rod 10, so the rod 10 and the clamp unit 38 are separated from each other as shown in the figure. It is possible to move relative to the center, up and down. That is, when hydraulic pressure is not acting on all of the annular oil chambers 22a, 22b, and 22c, the friction type clamp device is in a released state.

Next, the annular oil chamber 2 is connected to the clamp hydraulic circuit (not shown).
If hydraulic pressure is applied to 2, the collared sleeve 14
is pushed towards the rod 10, which causes the rod 10 to
axial movement is restricted. For example, the annular oil chamber 22
When hydraulic pressure is applied to a, the flanged sleeve 14a is elastically deformed in the radial direction, and its inner diameter is pressed against the outer diameter of the rod 10. As a result, the rod 10 is clamped to the outer cylinder 12a via the flanged sleeve 14a. That is, the friction type clamp device is in a fastened state. The step of determining which of the clamp units 38a, 38b, and 38c should be supplied with hydraulic pressure to clamp the rod 10 is performed, for example, as follows. For example, if the load acting on the rod 10 gradually increases, for example, the controller 42 may select the lower clamp unit 38a first, and the comparator 40 may select the lower clamp unit 38a first. , a set value that is slightly smaller than the load that can be supported by the clamp unit 38a, and a set value that is slightly smaller than the load that can be supported by the clamp units 38a and 38b are set in advance. this is,
For example, the clamp units 38a and 38b are clamped while the load applied to the rod 10 is smaller than the load that can be supported by the clamp unit 38a, thereby preventing the rod 10 from slipping. In response to a command from the controller 42, the annular oil chamber 2 of the clamp unit 38a is supplied from a clamp hydraulic circuit (not shown).
When hydraulic pressure is supplied to 2a, the load W of the rod 10 is applied to the outer cylinder 12 via the flange 18a of the flange sleeve 14a.
a and is measured by a load sensor 28 fixed thereto. The load sensor 28 outputs a signal proportional to the load to the comparator 40. The comparator 40 compares two set values (set load) set internally with the measured value, and outputs no signal while the measured value of the load is smaller than the set value. When the measured value gradually increases and becomes larger than the smaller set value, a signal corresponding to the result is output to the controller 42. In response to the signal from the comparator 40, the controller 42 outputs a signal to the clamp hydraulic circuit so as to supply hydraulic pressure to the clamp unit 38b as well as the clamp unit 38a. Furthermore, when the measured value becomes larger than the larger set value, the comparator 40 applies a signal to the controller 42 in accordance with the result. The controller 42 controls all clamp units 38a in response to the signal from the comparator 40.
A signal is output to the clamp hydraulic circuit to supply hydraulic pressure to 38b and 38c. In this way, the clamp units 38a, 38b, and 38c can be selected and operated according to the magnitude of the load W.

(Second Embodiment) Next, the second embodiment shown in FIG. 2 will be described. A hole 16b and a through hole 16a concentric with the hole 16b are formed in the block-shaped stationary plate 16 in the axial direction, and a cylindrical rod 10 is fitted into the through hole 16a so as to be movable in the axial direction. . A clamp unit 78a is fitted between the hole 16b of the fixed platen 16 and the outer diameter of the rod 10.

This allows the clamp unit 78a to move within certain limits in the axial direction. The clamp unit 78a includes a cylindrical outer tube 52a, a collared sleeve 5 fitted into the inner diameter of the outer tube 52a, and fitted onto the rod 10.
4a. Note that two seal members 3 are provided between the inner diameter part of the outer cylinder 52a and the thin sleeve outer diameter part of the flanged sleeve 54a, as in the first embodiment.
0 is set. A load supporting oil chamber 26 is formed by the hole 16b of the fixed platen 16, the lower end of the lower end clamp unit 78a, and the outer diameter of the rod 10. Fixed plate 16
There is a pressure sensor 2 that measures the oil pressure in the load support oil chamber 26.
9 is attached. As a result, the load supporting oil chamber 26
is kept in a sealed state. A sealing member 32 is provided between the inner diameter of the flanged sleeve 54a and the outer diameter of the rod 10. A seal member 34 is provided between the outer diameter part of the rod 10 on the lower end side in the figure and the corresponding inner diameter part of the stationary plate 16, and the outer diameter part of the lower outer cylinder 52a and this A sealing member 36 is provided between the hole 16b of the fixed platen 16 and the inner diameter portion thereof corresponding to the hole 16b of the fixed platen 16. There are two clamp units 78b and 78b on the top of the clamp unit 78a.
78c are arranged in an overlapping state in the axial direction.

These configurations are the same as those of the clamp unit 38b of the first embodiment.
-Same as 38c. A signal from the pressure sensor 29 is input to a comparator 40. A controller 42 is connected to the comparator 40 . Comparator 40 and controller 4
2 is similar to the first embodiment, although there is a difference in whether the signal handled is a load signal or a pressure signal.

Next, the operation of this second embodiment will be explained using FIG. 4. In the figure, the horizontal axis represents the pressure in the load support oil chamber 26, and the vertical axis represents the load W and load f applied to the rod 10.

is the maximum load that can be supported by the lower clamp unit 78a, and load f2 is the maximum load that can be supported by the lower clamp unit 78a, and the load f2 is the maximum load that can be supported by the lower clamp unit 78a.
Total maximum load that can be supported by 8a and 78b, load f
3 is the total maximum load that can be supported by all clamp units 78a, 78b, and 78c. Comparator 4 in advance
As shown in FIG. A set load wb (pressure pb) smaller than B) is set. As a result, when the clamp unit 78a first performs a clamping operation and the load supported thereby increases and becomes equal to the set load Wa, the clamp unit 78a
In addition to the clamp unit 8a, the clamp unit 78b is also controlled to perform a clamping operation to prevent the rod 10 from slipping. The relationship between the load f2 and the set load wb is also the same, and when the load f2 becomes equal to the set load wb,
In addition to the clamp units 78a and 78b, the clamp unit 78c is also controlled to perform a clamping operation.

Releasing and fastening of the rod IO is performed in the same manner as in the first embodiment. For example, hydraulic oil is supplied from a hydraulic circuit (not shown) to the lower annular oil chamber 62a through the oil flow path 64a, and the lower clamp unit 78a clamps the rod 10.
When a load Wa is applied to the rod 10 in a clamped state, the load W is transmitted to the outer cylinder 52a via the collar 58a of the collared sleeve 54a, pushes the lower end of the outer cylinder 52a, and pushes the lower end of the outer cylinder 52a. Therefore, the pressure Pa in the load supporting oil chamber 26
occurs. Pressure sensor 29 outputs this pressure Pa to comparator 40. The comparator 40 compares two internal set values (set pressures) with the measured value output from the pressure sensor 29, and does not output a signal while the measured pressure value is smaller than the set value. When the measured value becomes larger than the set value Wa, a corresponding signal is output to the controller 42. The controller 42 sends a control signal to a clamp hydraulic circuit (not shown) to operate the clamp units 78a and 78b so as to operate the clamp unit 78b according to the signal from the comparator 40. Next, when the load acting on the rod 10 increases and reaches the load wb, a corresponding signal is output from the comparator 40 to the controller 42, and a command signal from the controller 42 causes the upper oil flow path 64b to be controlled. The hydraulic oil is then supplied to the upper annular oil chamber 62c, and the upper clamp unit 7
8c is also caused to perform a clamping action. That is, all the clamp units 78a to 78c are in a clamped state.

This makes it possible to support up to the maximum load C.

(Third Embodiment) FIG. 3 shows a third embodiment of the friction type clamp device of the present invention. The block-shaped movable platen 56 has a hole 56b and a through hole 56a concentric with the hole 56b. A rod 50 is fitted into the through hole 56a of the movable platen 56 so as to be relatively movable. The rod 50 has a lower end portion fixed to a fixed portion in the figure. A clamp unit 78a is fitted between the hole 56b of the movable platen 56 and the rod 5o so as to be movable in the axial direction. The configuration of the clamp unit 78a is similar to that described in the first embodiment. At the upper part of the clamp unit 78a in the figure, there are clamp units 78b and 7.
8c are arranged in an overlapping state in the axial direction. The configurations of clamp units 78b and 78c are similar to those described in the second embodiment. Hole 56b of movable platen 56,
The lower end of the lower clamp unit 78a and the rond 50
A load-supporting oil chamber 66 is formed by the outer diameter of. An MFa pressure regulating valve 68 and a hydraulic power source 70 are connected to a pipe 60 communicating with the load support oil chamber 66, and the electromagnetic pressure regulating valve 68 is controlled by a setting device 74 and an amplifier 72. - The setting device 74 is the load supporting oil chamber 6
It is possible to send a signal to the amplifier 72 and to the controller 76 to set the pressure supplied to the pump 6 . The controller 76 appropriately selects clamp units 78a, 78b, and 78c according to the control signal, and sends a control signal to a clamp hydraulic circuit (not shown) to select a predetermined one of the clamp units 78a, 78b, and 78c. It is possible to supply hydraulic pressure. This third embodiment is optimal when the load applied to the rod 50 can be predicted.

The operation of this third embodiment is similar to that of the second embodiment, except that the rod 50 is fixed, the movable platen 56 moves, and the oil pressure of the load support oil chamber 66 (i.e., the size of the supported load) can be adjusted. It is similar to that of the example.

For example, assume that the clamp unit 78a can support a load of 400 tons, the clamp unit 78b can support a load of 200 tons, and the clamp unit 78c can support a load of 100 tons.
Assuming that each can be supported, the setting device 7
By increasing the number of preset loads set to 4 to 6, selecting and combining the clamp units 78a to 78c, and supplying hydraulic pressure to these, a load of 700 tons or less can be supported. That is, the clamp unit 78c
100 tons or less with clamp unit 78b alone, 200 tons or less with clamp unit 78b alone, 300 tons or less with clamp unit 78c and 78b, 400 tons or less with clamp unit 78a alone, 500 tons or less with clamp unit 78c and 78a, clamp unit 78b and 7
600 tons or less using 8a, clamp unit 78c
, 78b and 78a, each can support up to 700 tons. By performing such stepwise control, the lifespan of the flanged sleeves 54a to 54c can be made more even.

In the above description of the first embodiment, it is assumed that the load W acting on the rod 1° is detected by the load sensor 28 fixed to the outer cylinder 52a. It is also possible to detect the load W from the amount.

(G) As described in detail, according to the present invention, the cycle time can be shortened when the load is small. Furthermore, since the length of each flange sleeve can be shortened, the thin inner diameter portion of the sleeve can be easily machined with high precision, and the device can be made inexpensive.

Also, since we used multiple sleeves with flanges,
The stress acting on the flange sleeve can be dispersed, and the durability of the device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a friction type clamping device according to a first embodiment of the present invention, FIG. 2 is a diagram showing a friction type clamping device according to a second embodiment of the present invention, and FIG. 3 is a diagram showing a friction type clamping device according to a second embodiment of the present invention. FIG. 4 is a diagram illustrating the relationship between the load supported by the clamp unit and the oil pressure of the load supporting oil chamber, and FIG. 5 is a diagram illustrating a conventional friction clamp device. 10---Rod, 12a, 12b, 12c...Outer cylinder, 14a, 14b, 14c...Sleeve with collar, 1
6...Fixed plate, 18a/18b 18c...Brim portion, 22a/22b
22c - Annular oil chamber, 24a/24b 24
c o oil flow path, 26... load supporting oil chamber, 28... load sensor, 29... pressure sensor, 38a
・38b・38c ・Clamp unit, 42...
Controller, 50... Rod, 52a 52b 52
c Outer cylinder, 54a/54b 54c ・Sleeve with flange, 56... Movable platen, 66. ・Load supporting oil chamber, 76. ・Controller, clamp unit.

Claims (1)

[Claims] 1. A rod (10) and a plurality of clamp units (38a, 38
b, 38c), and each clamp unit (
38) is composed of an outer cylinder (12) and a collared sleeve (14) which is fitted into the inner diameter part of the outer cylinder (12) and is fitted so as to be movable relative to the rod (10) in the axial direction. The sleeve (14) with a flange is formed with a flange (18) that can push the outer cylinder (12) in the axial direction where the load acts, and the inner diameter of the outer cylinder (12) and the sleeve with a flange ( An annular oil chamber (22) is formed between them by the outer diameter part of the rod (10) and the inner diameter part of the flanged sleeve (14). When oil pressure is not acting on the annular oil chamber (22), the rod (10) and the outer cylinder (12) can move relative to each other in the axial direction, and when oil pressure is acting on the annular oil chamber (22), the rod (10) and the outer cylinder (12) can move relative to each other in the axial direction. A friction type clamp device configured to be connected to an outer cylinder (12) via a flange sleeve (14). 2. Rod (10) and clamp unit (38a/3
A load sensor (28) for detecting the load is provided on either of the clamp units (38a, 38b, 38c) according to the magnitude of the signal, and hydraulic pressure is applied to it. A controller that outputs the signal to be supplied (
42) The friction type clamp device according to claim 1. 3. It has a fixed plate (16) fitted to the clamp unit (78a) located at the end in the direction of load application, and the fixed plate (16) is fitted to the clamp unit (78a) at the end.
), and is fitted with the rod (10) and is movable relative to it in the axial direction, and the inner diameter part of the stationary platen (16) and the clamp unit (78a) at the end part ) and the rod (10)
A load support oil chamber (26) is formed by the outer periphery of the load support oil chamber (26), and a pressure sensor (29) that detects the pressure acting on the load support oil chamber (26) and a clamp unit according to the magnitude of the signal from the pressure sensor (29). 2. The friction type clamp device according to claim 1, further comprising a controller (42) for outputting a signal for selecting one of (78a, 78b, 78c) and supplying hydraulic pressure to the selected one. 4. Clamp unit (78a) located at the end in the direction of load application
It has a movable platen (56) fitted together, one end of the rod (50) is fixed to a fixed part, and the movable platen (56) has a clamp unit (78a) at its end.
) and can move relative to the rod (5) in the axial direction.
0) and is movable relative to this in the axial direction, and the clamp unit (
A load supporting oil chamber (66) is formed by the distal end of the rod (78a) and the outer periphery of the rod (50), and the clamp unit (78
2. The friction type clamping device according to claim 1, further comprising a controller (76) for outputting a signal for selecting one of (a, 78b, and 78c) and supplying hydraulic pressure to the selected one.