JPH03286040A - Dynamic damper of vehicle - Google Patents

Abstract

PURPOSE:To restrain oscillation of a vehicle body effectively by holding a balance weight on either side of the front or rear of a vehicle body so that it may vibrate through a holding spring, and making an element for the balance weight changeable. CONSTITUTION:A balance weight 24 is provided on either side of the front or rear of a vehicle body so that it may move vibrate through a holding spring 22. The pitching and bouncing which are apt to occur during vehicle running are restrained by making the balance weight 21 vibrate against the holding spring 22. There is also provided a changing means which changes elements such as the mass and the mount of inertia of the balance weight 21 for the determination of the characteristic frequency of the dynamic damper 20. If the characteristic frequency of a main vibration system consisting of the vehicle body and so forth changes, the condition of the element of the balance weight 21 is changed by the changing means to maintain the characteristic frequency of the dynamic damper 20 optimum in oscillation restraint all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dynamic damper for a vehicle such as a wheel loader.

(Prior Art) As a dynamic damper for a wheel loader, there is, for example, one shown in Japanese Patent Application Laid-Open No. 63-265023.

In this device, the load holding side oil chamber of the boom cylinder in the work equipment is connected to an accumulator, and the work equipment as a mass member and the accumulator that acts as a spring form a dynamic damper. Pitching, bouncing, etc. of the vehicle body are suppressed.

By the way, with the above, during excavation work, it is necessary to shut off the oil passage between the boom cylinder and the accumulator to protect the accumulator from high-pressure hydraulic oil, and therefore it is necessary to provide an on-off valve between the boom cylinder and the accumulator. was there.

In addition, in the above-mentioned model, when the dynamic damper is activated, the load-side oil chamber needs to be in communication with the tank in order to allow the boom cylinder to expand and contract.
It was necessary to interpose a connecting means between the midway part of the load-side pipe and the tank to connect the two to a communicating state and a disconnected state.

(Problems to be Solved by the Invention) As mentioned above, in the conventional dynamometer damper, in addition to the accumulator that constitutes the dynamic damper, it is necessary to have an on-off valve and a connection means, and the hydraulic circuit of the working device is complicated. There was a problem that the cost was high.

Further, when changing from the traveling position to the working position or vice versa, it is necessary to operate the on-off valve and the connecting means, which is very troublesome.

Furthermore, if you forget to perform the above operation when transitioning from a working position to a running position, the dynamic damper will simply not operate; however, when transitioning from a running position to a working position,
If the above operation is forgotten, there is a problem that the accumulator will be damaged.

Therefore, it is necessary to have a safety device in case the user forgets to perform the above operation, or a device that automatically performs the above operation.
Furthermore, there is a problem of complicating the dynamic damper and increasing cost.

Furthermore, since an accumulator provided in the hydraulic circuit of the working device is used, there is also a problem in that the dynamic damper cannot be operated when the working device is operated by the hydraulic circuit during work.

An object of the present invention is to provide a dynamic damper for a vehicle that can solve the above problems.

(Means for Solving the Problems) In order to solve the above problems, the means adopted by the present invention are as follows:
Balance weights are provided on the front and rear sides of the vehicle body so as to be able to vibrate via retaining springs, and a changing means is provided for changing elements related to the balance weights that are involved in calculating the natural frequency of the dynamic damper. .

Note that the element related to the balance weight may be the mass of the balance weight.

Further, the balance weight may be swingably supported on the vehicle body by a pivot shaft, and the balance weight-related element may be the moment of inertia of the balance weight.

Furthermore, the balance weight may be composed of an oil tank provided in the vehicle body via a holding spring and oil inside the oil tank, and the changing means may be a device for adjusting the amount of oil in the oil tank. be.

Further, the holding spring may be a compression coil spring to hold the balance weight in a pinched manner, and the changing means may be a device that presses the balance weight via the holding spring.

Furthermore, the balance weight is comprised of a frame body that is swingably supported on the vehicle body by a left-right pivot shaft, and a weight body that is swingably supported on the frame body by a left-right pivot shaft. The changing means may be a device interposed between the frame and the weight body to rotate the weight body.

In addition, the balance weight is composed of a frame body which is swingably supported on the vehicle body by a pivot shaft in the left and right direction, and a weight body, and the weight body is attached to the frame body with respect to the pivot part of the balance weight. In some cases, the weight body is provided so as to be movable back and forth, and a changing means is interposed between the frame and the weight body to move the weight body back and forth with respect to the pivot portion of the balance weight.

Furthermore, the vehicle body is equipped with a working part that can be raised and lowered via an elevating cylinder, and when the oil pressure in the load holding side oil chamber of the elevating cylinder becomes large, a changing means is operated to change the natural frequency of the dynamic damper. In some cases, means are provided to reduce the size.

The vehicle may also be provided with a sensor for detecting acceleration in the vertical direction of the vehicle body, means for calculating the vibration frequency of the vehicle body from the detected acceleration, and means for operating the changing means in accordance with the calculated vibration frequency. be.

Further, the balance weight is pivotally supported on the vehicle body by a pivot shaft in the left and right direction, and the balance weight is movable in the front and back direction with respect to the pivot shaft, and between the vehicle body and the balance weight, A holding spring that holds the balance weight so that it can move up and down, and an adjustment spring that elastically pulls the balance weight forward may be interposed.

Also, a shock absorber may be interposed between the vehicle body and the balance weight.

(Function) When the vehicle is running, depending on the undulations of the road surface, or
The vehicle body tends to pitch or bounce during acceleration or deceleration.

At this time, the balance weight of the dynamic damper vibrates against the holding spring, thereby suppressing pitching, bouncing, etc. of the vehicle body.

When conditions change, such as when the natural frequency of the main vibration system consisting of the vehicle body changes, the mass of the balance weight, moment of inertia, etc. are changed to adjust the natural frequency of the Dynagotsu damper. changes, thereby responding to changes in the conditions described above.

(Embodiment) Hereinafter, a first embodiment in which the present invention is applied to a wheel loader will be explained based on the drawings of FIGS. 1 to 3. FIG.
and a working device 2 provided at the front of the vehicle body 1.

The vehicle body 1 includes a vehicle body 6 consisting of front and rear frames 4, 5, etc.
It has left and right front and rear wheels 7.8, a cabin 9, etc.

Further, the working device 2 includes a pair of left and right booms 11 that are pivotably supported on the front frame 4 so as to be able to rise and fall freely, and the front frame 4 and each boom 1.
A pair of left and right boom cylinders 12 are interposed between the boom cylinders 12 and a packet 13 rotatably supported on the front end of the boom 11.
and a packet cylinder 14 interposed between the previous frame A and the packet 13.

As shown in FIGS. 1 and 3, the rear frame 5 includes a pair of left and right side plates 16, a rear plate 17 that connects the rear ends of the side plates 16, and a rear frame 5 that stands up from the rear parts of the side plates 16 and the rear plate 17. It has a pair of left and right upstanding plates 18, etc., which are provided and whose upper ends are connected.

Reference numeral 20 designates a dynamic damper, which includes a balance weight 21 that balances the load, a pair of left and right holding springs 22 that hold the balance weight 21 so that it can swing up and down, and a pair of left and right shock absorbers 23 that damp the up and down swing of the balance weight 21. has.

The balance weight 21 includes a pair of left and right arms 26, an operating cylinder 27, a weight body 28, and the like.

Each arm 26 is located on the outside of each side plate 16 of the rear frame 5, and its front end is pivoted to each side plate 16 by a pivot shaft 30 in the left-right direction so that it can freely swing up and down. is visible from the front rod 31 on the front side and the rear part 32 on the rear side.

The rear part 32 has a groove shape that opens inward, and the front rod 31
The arm 26 is fitted onto the outside so as to be movable in the longitudinal direction, so that the arm 26 is extendable and retractable, and an elongated hole 33 is formed in the side wall portion of the arm 26 in the longitudinal direction.

Each actuating cylinder 27 is interposed between the front rod 31 and the rear 32 of each arm 26.

The weight main body 28 is fixed to the rear end of the rear part 32 of each arm 26, is located behind the rear plate 17 of the rear frame 5, and has a horizontally elongated shape.

The holding spring 22 and the shock absorber 23 are interposed between the standing plate 18 of the rear frame 5 and the front part of the front bar 31 of each arm 26, but from the front part of the front bar 31, the long hole in the rear part 32 is inserted. 33, movably inserted hook shafts 35 and 36 are protruded, and these are connected to the holding spring 22 and the shock absorber 2.
The lower end of 3 is attached.

According to the embodiment configured as described above, when the wheel loader is running, the vehicle body 1 and the working device 2 of the wheel loader may pitch or pitch depending on the undulations of the road surface or when accelerating or decelerating. Try bouncing.

At this time, the balance weight 21 of the dynamic damper 20 swings up and down against the holding spring 22 and the shock absorber 23, and the balance weight 21 moves in the opposite direction to the direction in which the rear part of the vehicle body 1 attempts to move. Therefore, pitching, bouncing, etc. of the vehicle body 1 and the working device 2 are suppressed, and the swinging of the balance weight 21 can also be attenuated quickly by the shock absorber 23.

By the way, the natural frequency of the main vibration system exerted by the vehicle body 1 and the work device 2 is determined by the mass of the vehicle body 1 and the work device 2, and
The natural frequency of the Dynago Tsuta damper 20 is determined by the spring constants of the front and rear wheels 7.8, and the natural frequency of the Dynago Tsuta damper 20 is determined by the balance weight 21.
It is determined by the moment of inertia of , the spring constant of the holding spring 21, the distance from the pivot shaft 30 to the holding spring, etc.

Then, the mass ratio and natural frequency ratio of both the main vibration system and the dynamic damper 20, and the dynamic damper 20 are adjusted so that the peak of the resonance curve of the main vibration system is as low as possible.
If the damping coefficient etc. of the shock absorber 23 are set,
No matter what the frequency of the external force acting on the vehicle body 1 and the working device 2 is, pitching and bouncing of the vehicle body 1 and the working device 2 can be satisfactorily suppressed.

In this case, the mass of the working device 2 differs between the case where the packet 13 of the working device 2 is not loaded with earth and sand and the case where it is loaded, and the natural frequency of the main vibration system also differs accordingly.

Therefore, in the above case, the arm 26 of the balance weight 21 is expanded and contracted by the actuation cylinder 27 depending on the presence or absence of the load in the packet 13 and its weight, and the pivot shaft 30
By adjusting the distance from to the center of gravity of the balance weight 21, the natural frequency of the dynamic damper 20 is changed according to the mass and natural frequency of the main vibration system. Pitching and bouncing of the vehicle main body 1 and the working device 2 can be satisfactorily suppressed regardless of the presence or absence of the vehicle body 1 and its weight.

In the above case, if there is no shock absorber 23, even if the distance from the pivot shaft 3o to the center of gravity of the Haran weight 21 is adjusted, the dynamic damper 20
The frequency of the external force that can be well handled is limited within a predetermined range, but otherwise the effect is the same.

Further, in the above case, when there is no load in the packet 13, the arm 26 of the balance weight 21 is made the shortest, and as the weight of the load increases, the arm 26 is extended.

4 and 5 show a second embodiment of the present invention, in which a balance weight 21 is pivotally supported on a rear plate 17 of a rear frame 5, and a balance weight 21 is attached to a pivot shaft 30 on the rear plate 17.
a frame body 38 having a U-shaped frame shape in plan view and pivoted by;
The weight body 28 is rotatably supported on a left-right pivot shaft 39 at the rear end of the frame 38, and the weight body 28 is located at the position shown by the solid line in FIG. The position can be freely changed between the position and the position rotated 90' rearward.

A holding spring 22 and a shock absorber 23 are interposed between each rear plate 17 of the rear frame 5 and each side surface of the frame body 38 of the balance weight 21, respectively.

Further, an actuation cylinder 27 for rotating the weight body 28 is interposed between the frame body 38 and the weight body 28.

Sensors 42 and 43 detect the tire pressures of the front and rear wheels 7.8, respectively.

Reference numeral 44 denotes a control device, which includes calculation means for calculating the position of the center of gravity in the longitudinal direction of the wheel loader from the tire pressures of the front and rear wheels 7.8 detected by sensors 42. Comparison means compares the position of the center of gravity with the standard center of gravity position when there is no loaded object and controls the control valve 45 of the actuating cylinder 27 based on the difference.

According to the embodiment configured as described above, the sensor 42.4
3 detects the tire pressures of the front and rear wheels 7.8, respectively, and the calculation means of the control device 44 calculates the center of gravity position of the wheel loader from the tire pressures.

Then, the comparison means of the control device 44 compares the calculated center of gravity position with the standard center of gravity position, but if there is no loaded object in the packet 13, the actuation cylinder 27 is not operated because the two are the same. First, the weight body 28 is at the frontmost position, as shown by the solid line in FIG.

When the packet 13 is loaded with a load, the calculated center of gravity position is different from the standard center of gravity position, so the comparing means operates the control valve 45 based on the difference in the repositioning and operates the actuating cylinder 27. Then, the weight body 28 is rotated to return the center of gravity of the wheel loader to the standard center of gravity, for example.

As described above, the center of gravity position of the balance weight 21 is changed, and the natural frequency of the dynamic damper 20 is changed in accordance with the mass and natural frequency of the main vibration system.

6 and 7 show a third embodiment of the present invention,
Recessed guide portions 47 are formed in the front-rear direction on the inner surfaces of the left and right sides of the frame body 38, and protrusions 48 are provided on the guide portions 47 to protrude from the left and right sides of the weight body 28. are engaged so as to be slidable in the front-rear direction.

Then, the weight body 28 is operated to move in the front-back direction by the actuation cylinder 27.

FIG. 8 shows a fourth embodiment of the present invention, in which a balance weight 21 is used as an oil tank, and an adjustment cylinder 50 that stores oil and adjusts the amount of oil in the balance weight 21 is installed in the vehicle body 1. The adjustment cylinder 50 includes a cylinder 51 that stores oil, and a piston 52 that is provided within the cylinder 51 so as to be slidable in the vertical direction.

The actuation cylinder 54 is connected to the piston 52 of the adjustment cylinder 50.
to adjust the amount of oil in the balance weight 21.

A sensor 57 detects the oil pressure in the head side oil chamber 58, which is a load holding side oil chamber in the boom cylinder 12.

The control device 44 compares the oil pressure detected by the sensor 57 with the standard oil pressure when there is no load in the packet 13, and operates the control valve 45 in accordance with the difference.

According to the embodiment configured as described above, when there is a load in the packet 13, the sensor 5 responds to the weight of the load.
7, the detected oil pressure increases.

Then, depending on the difference between this oil pressure and the standard oil pressure, the control valve 45
is actuated to actuate the actuating cylinder 54, which actuates the piston 52 and causes the balance weight 2 to actuate.
1, the mass of the balance weight 21 is changed, and the natural frequency of the dynamic damper 20 is changed.

FIG. 9 shows a fifth embodiment of the present invention, in which a balance weight 2
A holding spring 22, which is a compression coil spring, is arranged above and below the balance weight 21 so as to be able to move up and down.

Reference numerals 59 and 60 denote upper and lower support plates, which are respectively provided between the upper and lower ends of the compatible membrane plate 18, and which support the upper support plate 59 and the upper retaining spring 2.
An operating cylinder 61 is interposed between the upper support plate 59 and the balance weight 21, and a shock absorber 23 is interposed between the upper support plate 59 and the balance weight 21.

Further, the lower support plate 60 receives the lower holding spring 22.

A sensor 63 detects the acceleration of the vehicle body 1 in the vertical direction.

The control device 44 has a calculation means for calculating the vibration frequency of the vehicle body 1 from the acceleration detected by the sensor 63, and a control means for controlling the control valve 45 of the actuating cylinder 61 according to the calculated vibration frequency.

According to the embodiment configured as described above, the vehicle body 1 and the working device 2 of the wheel loader tend to pitch or bounce depending on the undulations of the road surface or during acceleration or deceleration during traveling.

At this time, the sensor 63 detects the gravitational acceleration of the vehicle body 1, the control device 44 calculates the vibration frequency of the vehicle body 1, and operates the control valve 45 according to this vibration frequency.

As a result, the actuating cylinder 61 is actuated, and the vehicle body 1
A pressure corresponding to the frequency of vibration is applied to the balance weight 21 via the upper holding spring 22, thereby substantially increasing or decreasing the mass of the balance weight 21 and changing the natural frequency of the dynamic damper 20.

In other words, the natural frequency of the dynamic damper 20 is always approximately equal to the frequency of the external force acting on the vehicle body 1, so that no matter what the frequency of the external force is, the vehicle body 1 and the work The device 2 hardly vibrates, and only the balance weight 21 vibrates.

FIG. 10 shows a sixth embodiment of the present invention, in which a pair of left and right brackets 67 are provided rearwardly protruding from the rear plate 17 of the rear frame 5, and a pivot shaft 30 is installed between the brackets 67. ing.

The front part of the balance weight 21 has a long hole 69 in the front-rear direction.
is formed, and the pivot shaft 30 is inserted into the elongated hole 69 so as to be movable in the longitudinal direction of the elongated hole 3°.

A hook shaft 71 projects rearward from the standing plate 18 of the rear frame 5, and a holding spring 22 is interposed between the hook shaft 71 and the balance weight 21.

Further, an adjustment spring 73 is interposed between the rear plate 17 of the rear frame 5 and the balance weight 21 to elastically pull the balance weight 21 forward.

According to the embodiment configured as described above, when the vehicle body 1 pitches, the centrifugal force acting on the balance weight 21 corresponds to the vibration frequency, that is, the magnitude of the angular velocity in the vertical direction of the rear portion of the vehicle body 1. Power changes.

Then, depending on the magnitude of the centrifugal force, the balance weight 21 moves back and forth against the adjustment spring 73, and the distance from the pivot shaft 30 to the center of gravity of the balance weight 21 changes, and the dynamic damper The natural frequency of 20 is changed so that it corresponds to a value that substantially matches or is close to the frequency of the external force acting on the vehicle body l.

In the embodiment, the balance weight is provided in the vehicle body so as to be movable up and down or swingable, but it may be provided so as to be swingable back and forth.

Further, in the embodiment, the balance weight is provided at the rear end of the vehicle body, but the balance weight may be provided at the front end of the vehicle body.

Incidentally, it is also possible to freely combine the above embodiments as appropriate.

Furthermore, the present invention is applicable to vehicles other than wheel loaders.

(Effects of the Invention) As described in detail above, according to the present invention, balance weights are provided on the front and rear sides of the vehicle body so as to be movable up and down or swingable back and forth via holding springs. Since the dynamic damper is configured with a spring, the structure is simple and can be manufactured at low cost.
When transitioning from running position to working position or vice versa,
It is very convenient as there is no need to perform any operations, and in the case of a vehicle equipped with a working device, the dynago vine damper can be operated even when the working device is operated by the hydraulic circuit. .

In addition, since a change means is provided to change the balance weight-related elements involved in calculating the natural frequency of the dynamic damper, changes in conditions such as changes in the natural frequency of the main vibration system consisting of the vehicle body etc. Even if this occurs, pitching and bouncing of the vehicle body can be suppressed favorably.

Furthermore, according to the eighth aspect of the invention, it is possible to automatically make the Dynachan damper respond to changes in the natural frequency of the main vibration system due to the loading of earth and sand on the working section.

Further, according to claim 9 and 10, it is possible to automatically cope with any value of the frequency of the external force acting on the vehicle body very well.

Furthermore, if a shock absorber is provided as in claim 11, vibrations of the balance weight can be quickly damped.

In addition, in the case of claims 1 to 10, the shock absorber is provided, and the mass ratio and characteristic of both the main vibration system and the dynamic damper are adjusted so that the peak of the resonance curve of the main vibration system consisting of the vehicle body etc. is as low as possible. By setting the frequency ratio and the damping coefficient of the shock absorber of the dynamic damper, it is possible to satisfactorily suppress pitching and bouncing of the vehicle body, no matter what the frequency of the external force acting on the vehicle body is.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention,
Fig. 1 is a side view of the main parts, Fig. 2 is a side view of the wheel loader, Fig. 3 is a rear view of the main parts, and Figs. 4 and 5 show a second embodiment of the present invention. Fig. 4 is a side view of the main parts, Fig. 5 is a perspective view of the balance weight, Figs. 6 and 7 show a third embodiment of the present invention, and Fig. 6 is a side view of the main parts. FIG. 7 is a rear view of the balance weight, FIG. 8 is a partially sectional side view of the main part showing the fourth embodiment of the present invention, and FIG. 9 is a longitudinal sectional view showing the fifth embodiment of the present invention. FIG. 10 is a side view of essential parts showing a sixth embodiment of the present invention. 1...Vehicle body, 2...Working device, 1
1...Boom, 12...Boom cylinder (elevating cylinder), 13...Packet (working part), 20...Dinago vine damper, 21...
... Balance weight, 22 ... Holding spring, 23 ... Shock absorber, 26 ...
...Arm, 27...Operating cylinder, 28-
...Weight body, 3o...Pivot shaft, 3
8...Frame body, 42.43.57.63...
...Sensor, 44...Control device, 45...
...Control valve, 5o...Adjustment cylinder, 73...
...adjustment spring.

Claims (11)

[Claims] (1) A balance weight is provided on one front and rear side of the vehicle body so that it can vibrate via a holding spring, and a changing means is provided to change the balance weight-related elements involved in calculating the natural frequency of the dynamic damper. A dynamic damper for vehicles characterized by: (2) The dynamic damper for a vehicle according to claim 1, wherein the balance weight-related element is the mass of the balance weight. (3) Dynamics of the vehicle according to claim 1, wherein the balance weight is swingably supported on the vehicle body by a pivot shaft, and the balance weight-related element is a moment of inertia of the balance weight. damper. (4) The balance weight is composed of an oil tank provided in the vehicle body via a holding spring and oil inside the tank, and the changing means is a device for adjusting the amount of oil in the oil tank. Claim 2 or 3 characterized by
Dynamic damper for the vehicle listed. (5) The holding spring is a compression coil spring that holds the balance weight in a pinched manner, and the changing means is a device that presses the balance weight via the holding spring. dynamic damper for vehicles. (6) The balance weight includes a frame body that is swingably supported on the vehicle body by a left-right pivot shaft, and a weight body that is swingably supported on the frame body by a left-right pivot shaft. 4. The dynamic damper for a vehicle according to claim 3, wherein the changing means is a device interposed between the frame body and the weight body to rotate the weight body. (7) The balance weight is composed of a frame body that is swingably supported on the vehicle body by a pivot shaft in the left and right direction, and a weight body, and the weight body is attached to the frame body relative to the pivot part of the balance weight. It is equipped with a means to move forward and backward, and has a changing means.
4. The dynamic damper for a vehicle according to claim 3, further comprising a device interposed between the frame body and the weight body to move the weight body forward and backward with respect to the pivot portion of the balance weight. (8) The vehicle body is equipped with a working part that can be raised and lowered via an elevating cylinder, and when the hydraulic pressure in the oil chamber on the load holding side of the elevating cylinder becomes large, the change means is operated to cause the natural vibration of the dynamic damper. 8. The dynamic damper for a vehicle according to claim 1, further comprising means for reducing the number of dynamic dampers. (9) A sensor for detecting acceleration in the vertical direction of the vehicle body, a means for calculating the vibration frequency of the vehicle body from the detected acceleration, and a means for operating a changing means in accordance with the calculated vibration frequency. Claims 1 to 7 characterized in that
A dynamic damper for any vehicle described in any of the above. (10) A balance weight is swingably supported on the vehicle body by a pivot shaft in the left and right direction, and the balance weight is movable in the front and back direction with respect to the pivot shaft, and there is a space between the vehicle body and the balance weight. A dynamic damper for a vehicle, characterized in that a holding spring that holds a balance weight so that it can move up and down, and an adjustment spring that elastically pulls the balance weight forward are interposed. (11) Claims 1 to 10 characterized in that a shock absorber is interposed between the vehicle body and the balance weight.
A dynamic damper for any vehicle described in any of the above.