JPH10238504A - Vibration control device and method for hydraulic cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping effect, regardless of a ratio of rod side oil chamber pressure to bottom side oil chamber pressure by discharging the pressure oil of the rod side oil chamber to a hydraulic pipeline joined to a tank always kept at a low pressure level under the application of a pressure loss against the vibration of the rod side oil chamber. SOLUTION: A hydraulic pipeline 52 is joined to another hydraulic pipeline 55, and pressure oil is supplied to the rod side oil chamber 32R to a boom cylinder 32 from an accumulator 42 containing accumulated pressure, via a solenoid valve 41. As a result, the rod side oil chamber 32R of the boom cylinder 32 is fed with pressure oil from two passages and capable of maintaining proper pressure in a neutral condition. The compressed pressure oil of the bottom side oil chamber 32B of the boom cylinder 32 in this case is discharged under the application of a pressure loss thereto as the first vibration control stage, thereby dissipating inertia energy. At the same time, the pressure of the rod side oil chamber 32R of the boom cylinder 32 is raised to a desired level, thereby maintaining damping resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cylinder vibration damping apparatus and method, and more particularly, to a hydraulic excavator or other construction machine that is generated when a hydraulic cylinder that raises and lowers a boom is stopped. The present invention relates to vibration suppression control for damping vibration.

[0002]

2. Description of the Related Art FIG. 5 is a control circuit diagram of a cylinder 1 described in Japanese Utility Model Laid-Open Publication No. 6-65602. In the control circuit shown in FIG. 5, when the control valve "a" is switched from "on" to "off", a surge pressure is generated on the bottom 1a side during the switching. Thereafter, the pressure switch 4 detects that the operation is completely turned off. When the pressure sensor 5 detects that the bottom pressure is rapidly increasing, and then detects that the bottom pressure is rapidly increasing, the pressure sensor 5 determines that the bottom pressure is rapidly reduced. During this time, the electromagnetic switching valve 8 that short-circuits the cylinder rod side line 9 and the bottom side line 7 is turned "on", and the bottom side pressure oil can be released to the rod side or the tank T to suppress the bottom side pressure rise. , Boom 2 after this
The force (pressure) for pushing up the cylinder is weakened, and the expansion and contraction of the cylinder 1 can be quickly converged. Then, when the pressure sensor 5 detects that the bottom pressure is rapidly decreasing,
The electromagnetic switching valve 12 that gives a pilot signal to the safety valve integrated type negative control variable throttle 3 is turned “on” for a certain period of time to increase the pump discharge pressure and to short-circuit the pump discharge pressure line 6 and the cylinder bottom side line 7 with the electromagnetic switching valve 10. Similarly, it is turned on for a certain period of time to supply pressure oil to the cylinder bottom side. This is an example of an active damping device for so-called bottom pressure.

FIG. 6 is a hydraulic circuit diagram showing a shock prevention device for a working machine described in Japanese Patent Application Laid-Open No. 63-30601. The shock-preventing cylinder 37 arranged so as to communicate with the passages 25 and 28 to the boom cylinder 26 in FIG. 6 moves its piston 39 in accordance with the increase and decrease of the hydraulic pressure in each passage 25 and 28, This absorbs the shock at the time of lifting and lowering the work implement. This is an example of a so-called push damping device.

[0004]

First, in the vibration damping device shown in FIG. 5, although the pressure fluctuation on the bottom side is actively controlled, the pressure on the rod side is controlled by the push control (depending on the control of the solenoid valve 10, depending on the control of the solenoid valve 10). Semi-active control). In this case, since the determination of the supply / discharge control of the pressure oil on the bottom side is performed only by the pressure sensor provided on the bottom side, there is the following problem. The boom holding pressure in the neutral state fluctuates variously due to fluctuations in the stop position, load, and the like of the work implement. In addition, the kinetic energy at the time of stoppage generated on the bottom side varies depending on the speed of the work machine. Therefore, unless the boom holding pressure at the time of operation neutral is accurately derived and the supply / discharge control of the bottom side hydraulic oil is performed so as to correspond to the holding pressure, the boom will descend more than the boom operation amount. Conversely, on the contrary, the boom does not descend but there is a problem that effective damping cannot be performed. In addition, there is a risk that the boom will drop when the solenoid valve or the like fails.

[0005] The damping effect on the rod side is only a damping effect of short-circuiting to the bottom passage, but when the pressure on the bottom side is higher than the value considering the area ratio, the pressure oil on the rod side is reduced. It is not discharged to the bottom side, and no damping effect is exhibited. Also, the pressure oil supplied to the rod side is a flow rate supplied only from the bottom side, and there is a problem that a sufficient damping effect cannot be obtained. This inconvenience is a problem that the passive vibration damping device shown in FIG. 6 also has.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances in the prior art, and has as its object to reduce the vibration of a working machine when operation is stopped more effectively and safely, thereby improving operability. It is an object of the present invention to provide a hydraulic cylinder vibration damping device and a method for improving the hydraulic cylinder.

[0007]

In order to achieve the above object, according to the first and second aspects of the present invention, a variable displacement hydraulic pump driven by a power source and a discharge flow rate of the variable displacement hydraulic pump are changed. A swash plate control unit, a hydraulic cylinder driven by pressure oil discharged from the variable displacement hydraulic pump, a working machine which moves up and down by driving the hydraulic cylinder, and supplies and discharges pressure oil to and from the hydraulic cylinder. A construction machine having a switching valve for controlling, an operating device having a lever, controlling the switching valve and the swash plate control unit, and a tank for temporarily holding the hydraulic oil discharged from the hydraulic cylinder. , The rod-side oil chamber of the hydraulic cylinder and the tank,
A hydraulic line that communicates with a controller that determines whether the lever state of the operating device is in a neutral state or an operating state; throttle means that applies pressure loss to pressure oil in the hydraulic line; and the operating lever of the operating device is in a neutral state. A shutoff valve that opens the passage of the hydraulic line when in the state, and shuts off the passage of the hydraulic line when the operation lever of the operating device is in the operating state.

According to a third aspect of the present invention, there is provided a vibration control cylinder having a piston built in a hydraulic circuit of a hydraulic cylinder for raising and lowering the work machine according to the configuration of the first aspect, and a hydraulic chamber on one side of the piston for raising and lowering. And the other hydraulic chamber is connected to the hydraulic path of the rod side chamber of the lifting hydraulic cylinder.

According to a fourth aspect of the present invention, there is provided a hydraulic line branching from a hydraulic line communicating with a rod-side oil chamber of the hydraulic cylinder for raising and lowering, and the operating device. And a pressure source for supplying pressure oil to the rod side oil chamber from the branched hydraulic line when the operation lever is in a neutral state.

According to a fifth aspect of the present invention, in the configuration according to the first and third aspects, it is determined whether or not the operation speed of the operation lever of the operation device is slow. A controller for outputting a signal to shut off is provided.

According to a sixth aspect of the present invention, in the first and third aspects, the lifting hydraulic cylinder is a boom cylinder, the operating device is for the boom cylinder, and the controller performs a boom operation. And outputs a signal for opening the shut-off valve only when it is turned off.

According to a seventh aspect of the present invention, in the configuration according to the first and third aspects, when the lever operation of the operating device is operated so as to return quickly to neutral, at least the swash plate control unit and the switching valve are switched. The controller for outputting a signal for delaying one of them transiently is provided.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a main part hydraulic circuit diagram of a hydraulic shovel illustrating a first embodiment of the present invention. In the drawing, reference numeral 31 denotes a boom mounted on an upper swing body of a hydraulic shovel (not shown), and 32 denotes a boom cylinder for raising and lowering the boom 31. There are things. For this,
This is not an essential point of the present case, but one configuration will be described here. 32R is a rod-side oil chamber of the boom cylinder 32. 32B is a bottom oil chamber of the boom cylinder 32. Reference numeral 33 denotes a variable displacement hydraulic pump which is a pressure source of the pressure oil supplied to the boom cylinder. A switching valve 34 controls the supply and discharge of the pressure oil discharged by the variable displacement hydraulic pump 33 by changing the passage area. Reference numerals 35 and 36 denote tanks in which the pressure oil discharged from the hydraulic equipment such as the switching valve 34 is temporarily stopped. Reference numeral 37 denotes a controller that performs arithmetic processing on the input signal and outputs an output signal. An operation device 38 has an operation lever, and operates the boom 3 to a desired position at a desired speed by tilting the operation lever by an operator. Reference numeral 58 denotes a vibration suppression cylinder which is driven by the pressure oil discharged from the boom cylinder 32 and supplies the pressure oil to the boom cylinder 32. 5
8R is a rod-side oil chamber of the vibration suppression cylinder 58;
58B is a bottom oil chamber. Reference numeral 40 denotes a throttle unit that applies a pressure loss to the pressure oil supplied to or discharged from the vibration suppression cylinder 58.
Here, the throttle means 40 may be provided on either the bottom side or the rod side of the vibration suppression cylinder 58, or may be provided on both sides. Further, the opening degree of the throttle means 40 may be variable. 41 is the boom cylinder 3
2 is a solenoid valve that shuts off the connection from the bottom side oil chamber 32B to the rod side oil chamber 58R of the vibration damping cylinder 58, and is driven by an output signal from the controller 59 (the throttling means 40 May be provided in the valve). Details of the passage configuration of the solenoid valve 41 will be described later.
42 is a rod-side oil chamber 32R of the boom cylinder 32
The accumulator supplies the appropriate flow rate instantaneously.
43 is a pressure source for accumulating pressure in the accumulator 42. 44 sets the pressure of the pressure source 43 and the rod-side oil chamber 32R of the boom cylinder 32.
This is a relief valve which is also a throttling means for discharging pressure oil to the tank 36 while giving pressure loss to the pressure oil discharged from the tank. (Here, the set pressure of the relief valve 44 is
The low pressure is set at around 50 kgf / cm ² . )

Next, the hydraulic path and the signal path will be described. Note that the signal may be an electric signal, a hydraulic pilot, or a mixture thereof, but is not an essential part in the present case. 45 is an operation signal Ic corresponding to the lever angle of the operation device 38,
9 is a path to be input. 46 is the operation signal Ic
Is a path through which a control signal Ia for driving the switching valve based on the control signal is sent from the controller 59 to the switching valve 34. 47 is the solenoid valve 4 based on the operation signal Ic.
1 is a path for sending a control signal Ib for driving the solenoid valve 1 from the controller 59 to the electromagnetic valve 41. Reference numeral 48 denotes a hydraulic line connecting the variable displacement hydraulic pump 33 to the switching valve 34. 49 is a pipe connecting the switching valve 34 and the tank 35. 50 is a pipeline connecting the switching valve 34 and the bottom oil chamber 32B of the boom cylinder 32. Reference numeral 51 denotes a pipe connecting the bottom side oil chamber 32 </ b> B of the boom cylinder 32 and the solenoid valve 41. 5
Reference numeral 2 denotes a pipe connecting the pressure source 43 and the electromagnetic valve 41, and the accumulator 42 and the relief valve 44 are connected in the middle thereof. The secondary side of the relief valve 44 is connected to the tank 35. 5
Reference numeral 3 denotes a pipe connecting the switching valve 34 and the rod-side oil chamber 32R of the boom cylinder 32. 54 is the pipeline 53 and the bottom side oil chamber 5 of the vibration suppression cylinder 58.
8B. Reference numeral 55 denotes a conduit connecting the solenoid valve 41 and the rod-side oil chamber 32R of the boom cylinder 32. 56 is the solenoid valve 41 and the tank 3
6 is a pipeline connecting the two. 57 is the vibration damping cylinder 58
Is a pipe connecting the rod-side oil chamber 58R and the solenoid valve 41. The throttle means 40 is provided in the middle of the pipe. 63 is a swash plate control unit for controlling the discharge flow rate of the variable displacement hydraulic pump 33.

FIG. 2 shows the state when the boom lowering operation is stopped.
It is operation | movement explanatory drawing of the hydraulic circuit of the principal part of the said invention. FIG.
(A) shows just before the stop of the boom lowering operation, that is, just before the operation lever of the operation device 38 (see FIG. 1) enters the neutral state (may be just after the neutral state). In this state, the switching valve 34 shuts off the hydraulic pipe line 50 connected to the bottom oil chamber 32B of the boom cylinder 32, and the rod-side oil chamber 32R of the boom cylinder 32 and the hydraulic pipe 32. It is in a position to block the road 53. The electromagnetic valve 41 is in a position where the pipeline 51, the pipeline 55, and the pipeline 52 are shut off, and the hydraulic pipeline 57 and the hydraulic pipeline 56 are connected. Therefore, the pressure oil in the rod side oil chamber 58R of the vibration damping cylinder 58 is
It is discharged to the tank 36. At the same time, pressure oil is being supplied to the bottom side oil chamber 58B of the vibration damping cylinder 58 from the hydraulic line 54 during the boom lowering operation, and the vibration damping cylinder 58 is driven to the left in the drawing. It is. The accumulator 42 is connected to the pressure source 43
Thus, the pressure is stored at the pressure set by the relief valve 44. In this state, the boom 31, which is a load, is moved by the inertia to the bottom side chamber 32B.
It operates in the direction to compress the pressure oil.

FIG. 2A shows that the controller 59 (see FIG. 1) recognizes that the operating state is in the neutral state, and outputs the control signal Ib to output the electromagnetic valve 4.
1 shows a state in which the lens is driven. In this state, the hydraulic pipeline 51 and the hydraulic pipeline 57 are in communication. Accordingly, the pressure oil in the bottom side oil chamber 32B of the boom cylinder 32 passes through the solenoid valve 41 and the throttle means 40 and is discharged to the rod side oil chamber 58R of the vibration damping cylinder 58 while losing pressure. (The allowable amount of pressure oil discharged from the bottom oil chamber 32B is
(Limited by the rod-side oil chamber 58R of the damping cylinder 58). Thereby, the vibration suppression cylinder 58 is
The pressure oil in the bottom oil chamber 58B is driven to the right in the drawing to be supplied to the rod oil chamber 32R of the boom cylinder 32. Further, the hydraulic line 52 and the hydraulic line 55
The pressure oil from the accumulator 42, which has been accumulated, passes through the electromagnetic valve 41 and is supplied to the rod-side oil chamber 32R of the boom cylinder 32. Thus, the rod-side oil chamber 32R of the boom cylinder 32 is
Appropriate pressure can be ensured in a neutral state by supplying pressure oil from two paths. As described above, as the first stage of the vibration damping control, inertia energy is dissipated by discharging the pressurized oil compressed in the bottom oil chamber 32B of the boom cylinder 32 while giving a pressure loss. The pressure in the rod-side oil chamber 32 of the cylinder 32 is increased to a desired pressure to secure damping resistance.

FIG. 2C shows a state in which the boom cylinder 32 is driven upward by the reaction force of the compressed bottom oil chamber 32B of the boom cylinder 32 in FIG. In this case, the boom cylinder 3
If the pressure oil of the rod-side oil chamber 32R of the second rod-side oil chamber 32R is higher than the pressure oil of the rod-side oil chamber 58R of the vibration damping cylinder 58,
When the pressure of the pressure oil in the bottom oil chamber 58B is lower than a value obtained by multiplying the pressure of the pressure oil in the rod oil chamber 58R by the area ratio of the vibration control cylinder 58 (= rod area / bottom area). The vibration damping cylinder 58 is driven to the left in the figure, and the pressure oil in the rod-side oil chamber 58R is
0, the boom cylinder 3
2 is discharged to the bottom side oil chamber 32B. Next, from the pressure of the pressure oil in the rod-side oil chamber 58R, the bottom-side oil chamber 5
When the pressure of the pressure oil 8B is higher than the pressure oil pressure in the rod-side oil chamber 58R multiplied by the area ratio of the vibration suppression cylinder 58, the vibration suppression cylinder 58 is not driven. However, when the pressure of the pressure oil in the rod-side oil chamber 58R reaches or exceeds the set pressure of the relief valve 44, the pressure oil in the rod-side oil chamber 58R is released from the hydraulic pipeline 55, the electromagnetic valve 4R.
1. The relief valve 4 via the hydraulic line 52
4 to the tank 36. In this way,
In the second stage of the vibration suppression control, the pressure oil can be discharged while giving a pressure loss even under a pressure condition in which the vibration suppression cylinder 58 is not driven.

FIG. 3 is a hydraulic circuit diagram of a main part of a hydraulic shovel according to a second embodiment of the present invention. In the figure, the difference from the first embodiment shown in FIG. 1 is that the electromagnetic valve 41 is different from the hydraulic line 55 when the solenoid valve 41 is driven. In FIG. 1, the pressure oil is supplied by the accumulator 42 at the time of the communication, but in the second embodiment shown in FIG. 3, the pressure oil is supplied through the throttle means 60 as a pipe communicating with the hydraulic pipe 55. A hydraulic line 61 to be discharged to the tank 36 is provided. In this vibration suppression control device, the boom cylinder 32 in the neutral state is
When the operation lever is returned from the boom lowering operation to the neutral state to secure an appropriate damping resistance in the rod-side oil chamber 32R, the swash plate control unit 63 of the variable displacement hydraulic pump 33 is driven. A transient characteristic such that the pump discharge flow rate is reduced later than the operation signal is added to the control signal Ip to be generated, and an appropriate closing pressure is generated in the rod-side oil chamber 32R. The throttle means 60 may be built in the solenoid valve 41.

FIG. 4 is a main part hydraulic circuit diagram of a hydraulic shovel according to a third embodiment of the present invention. In the figure, the difference from the second embodiment shown in FIG.
Is not provided. Therefore, the boom cylinder 32
Does not have the function of damping the pressure oil in the bottom oil chamber 32B. The rod-side oil chamber 32 of the boom cylinder 32
As for the function of damping R pressure oil, the swash plate control unit 6 of the variable displacement hydraulic pump 33 has the same function as the second embodiment of FIG.
When the closing pressure of the rod-side oil chamber 32R secured by adding the transient characteristic to the control of the control line 3 is neutralized, the hydraulic line 55
The tank 36 is discharged while giving a pressure loss to the tank 36 through a solenoid valve 62 that communicates with the hydraulic line 61.

[0020]

Since the present invention is constructed as described above, the following effects can be obtained. According to the first and second aspects of the present invention, when the lever operation is neutral, the hydraulic pipe that leads to the tank where the pressure oil in the rod-side oil chamber is always kept at a low pressure in response to the vibration of the rod-side oil chamber of the hydraulic cylinder that occurs By discharging while giving a pressure loss to the passage, a damping effect is always obtained regardless of the pressure ratio between the rod-side oil chamber and the bottom-side oil chamber.
In the operating state, the operability is not affected by shutting off the hydraulic line.

According to the third aspect of the present invention, effective damping can be achieved by discharging the pressure oil in the bottom oil chamber of the hydraulic cylinder while giving a pressure loss to the rod oil chamber of the vibration control cylinder. Further, since the amount of oil discharged is limited by the capacity of the rod-side oil chamber of the vibration suppression cylinder, it is possible to reliably hold down the working machine lifted and lowered by the hydraulic cylinder within an allowable value and to ensure safety. Can be. Further, the damping effect can be always obtained even under the condition of the pressure ratio between the rod-side oil chamber and the bottom-side oil chamber of the hydraulic cylinder in which the vibration-damping cylinder is not driven.

According to the fourth aspect of the present invention, even if the pressure of the pressure oil in the rod-side oil chamber of the hydraulic cylinder is low when the operation lever is in the operating state, the pressure oil is reliably supplied from the pressure source. , More effective damping is possible.

According to a fifth aspect of the present invention, when the operation speed of returning the operation lever to the neutral state does not involve a gentle shock, the shut-off valve is not opened and the meaningless discharge of pressure oil is prevented to prevent operability. Deterioration can be prevented.

According to a sixth aspect of the present invention, the shut-off valve is opened on the premise that the driven hydraulic cylinder is a boom cylinder. Therefore, when the operating condition does not drive the boom cylinder, the shut-off valve is not opened. It is possible to prevent unnecessary discharge of pressure oil and prevent deterioration of operability.

According to the seventh aspect of the present invention, the closing pressure of the rod-side oil chamber of the hydraulic cylinder can be easily secured, and the damping effect can be enhanced.

[Brief description of the drawings]

FIG. 1 is a main part hydraulic circuit diagram of a hydraulic shovel showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of a main part hydraulic circuit of the present invention.

FIG. 3 is a main part hydraulic circuit diagram of a hydraulic shovel illustrating a second embodiment of the present invention.

FIG. 4 is a main part hydraulic circuit diagram of a hydraulic shovel showing a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a vibration damping device according to the related art.

FIG. 6 is a diagram showing a vibration damping device according to the related art.

[Description of Signs] 33 Variable displacement hydraulic pump 63 Swash plate control unit 32 Hydraulic cylinder 34 Switching valve 38 Operating device 35, 36 Tank 59 Controller 50, 51, 52, 53, 54, 55, 56 Hydraulic pipeline 41, 62 , Shut-off valve

Claims (7)

[Claims] 1. A variable displacement hydraulic pump driven by a power source, a variable displacement hydraulic pump, a swash plate control section for changing a discharge flow rate of the variable displacement hydraulic pump, and a discharge from the variable displacement hydraulic pump. A hydraulic cylinder driven by pressurized oil, a working machine that moves up and down by driving the hydraulic cylinder, a switching valve that controls the supply and discharge of pressure oil to and from the hydraulic cylinder, In a construction machine having an operating device for controlling a plate control unit and a tank for temporarily holding the hydraulic oil discharged from the hydraulic cylinder, it is determined whether the lever state of the operating device is in a neutral state or an operating state. A controller, a hydraulic line communicating the rod-side oil chamber of the hydraulic cylinder with the tank, a throttling means for applying pressure loss to the pressure oil in the hydraulic line, and an operation lever of the operation device. And a shut-off valve for opening the passage of the hydraulic line when in a state, and shutting off the passage of the hydraulic line when an operation lever of the operating device is in an operating state. Cylinder damping device. 2. A variable displacement hydraulic pump driven by a power source, a swash plate control section for changing a discharge flow rate of the variable displacement hydraulic pump, and a pressure oil discharged from the variable displacement hydraulic pump. A hydraulic cylinder, a working machine that moves up and down by driving the hydraulic cylinder, a switching valve that controls the supply and discharge of pressurized oil to and from the hydraulic cylinder, and a lever, the switching valve and the swash plate control unit, A construction device comprising: an operating device that controls the operation of the hydraulic cylinder, a tank that temporarily holds the hydraulic oil discharged from the hydraulic cylinder, and a controller that determines whether the lever state of the operating device is in a neutral state or an operating state. The hydraulic cylinder is characterized in that when the operating lever of the operating device is in a neutral state, the hydraulic oil in the rod-side oil chamber of the hydraulic cylinder is discharged to the tank while giving pressure loss to the tank. Law. 3. A vibration damping cylinder having a piston built in a hydraulic circuit of a hydraulic cylinder for raising and lowering the work machine is connected to a hydraulic passage on one side of the piston to a hydraulic passage to a head side chamber of the hydraulic cylinder for lifting and lowering. 2. The vibration control device for a hydraulic cylinder according to claim 1, wherein the hydraulic chamber on the other side is provided so as to communicate with a hydraulic passage in a rod-side chamber of the hydraulic cylinder for raising and lowering. 4. A hydraulic pipeline branched from a hydraulic pipeline communicating with a rod-side oil chamber of the hydraulic cylinder for lifting and lowering, and a branch to the rod-side oil chamber when an operation lever of the operating device is in a neutral state. 4. A vibration control device for a hydraulic cylinder according to claim 1, further comprising a pressure source for supplying pressure oil from the hydraulic line. 5. The controller according to claim 1, wherein the controller determines whether the operating speed of the operating lever of the operating device is slow, and outputs a signal for shutting off the shutoff valve when the operating speed is slow. The hydraulic cylinder vibration damping device according to claim 1. 6. The system according to claim 6, wherein the lifting hydraulic cylinder is a boom cylinder, the operating device is for the boom cylinder, and the controller outputs a signal for opening the shutoff valve only when a boom operation is performed. 4. The vibration control device for a hydraulic cylinder according to claim 1, wherein: 7. The controller that outputs a signal that causes at least one of the swash plate control unit and the switching valve to transiently delay when the lever operation of the operating device is quickly returned to neutral. 4. The vibration damping device for a hydraulic cylinder according to claim 1, wherein the vibration damping device is provided.