JPS59231232A - Hydraulic shock absorber with mechanism compensating oil temperature - Google Patents

Abstract

PURPOSE:To obtain the compensation of temperature in its wide range, by providing an orifice, which generates a flow between oil chambers without acting on a damping force generating means, and changing this orifice in a wide range from its full opening to full closing by a spiral bimetal. CONSTITUTION:A spiral bimetal 30 and a control plate 31, which connects the end part of this bimetal 30 to be operated, are provided in a bottom valve 14. Then an orifice 32, which is opened and closed by the control plate 31 generating a flow between oil chambers 23, 13 without acting on a valve plate 16 being the damping force generating means, is further provided. A compensating mechanism of temperature is obtained by changing an opening area of this orifice.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber with an oil temperature compensation mechanism, which is suitable for application to suspension systems of automobiles.

In general, hydraulic shock absorbers are designed to obtain damping force by utilizing energy loss when hydraulic oil passes through a damping force generating means attached to a communication hole between liquid chambers. The viscosity (kinematic viscosity) of the hydraulic oil, which largely affects the magnitude of the damping force that can be obtained, changes depending on the oil temperature, as shown in FIG.

Therefore, the damping force characteristics, which were designed as design standards, change in response to changes in temperature, and as can be seen from FIG. 1, these changes change drastically as the oil temperature decreases. Further, this change in damping force appears as a change in ride comfort in the vehicle. That is, even if a desired damping force is set based on the kinematic viscosity at room temperature of about 23° C., as the oil temperature decreases, the damping force increases, which has a subtle effect on ride comfort.

Therefore, in recent years, so-called hydraulic shock absorbers with an oil temperature compensation mechanism have been developed, which compensate for changes in damping force due to changes in oil temperature and can obtain a substantially constant damping force over a wide range of oil temperatures. It is starting to be developed.

This type of hydraulic shock absorber with an oil temperature compensation mechanism is known, for example, in Japanese Patent Application Laid-Open No. 146080/1983. As shown in Fig. 2, this is done by sensing the temperature of the hydraulic oil filled in the two upper and lower oil chambers 3.4 in the cylinder 2 separated by the piston 1 with a bimetal 5. The control plate 6 and the piston 1 are rotated relative to each other by the arm shape of the bimetal 5 based on the change in the shape of the bimetal 5, and the opening area of the orifice 7 provided in the piston 1 and communicating between the oil chambers 3 and 4 is changed. This also prevents changes in damping force characteristics due to changes in oil temperature.

By the way, in this type of conventional hydraulic shock absorber, the third
As shown in Figures (a), (to), or Figure 4, since a T-shaped or U-shaped bimetal is used, the effective length of the bimetal 5 is short, and the bimetal 5 can withstand changes in oil temperature.
Since the amount of deformation is small, it is difficult to expect sufficient effects. The orifice 7, which is controlled to open and close by the control plate 6, is a passage that guides hydraulic oil that acts on the damping force generating means 8 attached to one of the open ends of the orifice 7. Accordingly, the oil chamber 3
．． In this type of hydraulic shock absorber, the energy loss caused by displacement flow of the hydraulic oil in the orifice 7 and the damping force generating means 8 is obtained as a damping force, and the opening of the orifice 7 is completely closed. I can't. In other words, the control plate 6 can only operate over a wide range from fully opening to fully closing the opening of the orifice 7, so the adjustment range of the damping force is limited.

The present invention has been made in view of the conventional situation,
A piston valve and a bottom nozzle equipped with a damping force generating means are arranged opposite to one open end of a communication hole that communicates between the oil chambers.
An orifice is provided in one or both of the loops to create a flow between the oil chambers that does not act on the damping force generating means,
A control plate to which the end of a spiral bimetal is operatively connected is attached to one open end of this orifice, and the control plate and the orifice are rotated relative to each other by the bimetal that responds to changes in oil temperature. In particular, the opening area of the orifice is changed to increase the amount of deformation of the bimetal in response to changes in oil temperature, and the control plate is configured to control the opening and closing of the orifice from fully open to fully closed. It is an object of the present invention to provide a hydraulic shock absorber that can be applied over a wide range of conditions and that can maintain a constant damping force over a wide temperature range.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 5 is a sectional view of a main part of a hydraulic shock absorber showing an embodiment of the present invention. In the figure, 11 is an outer cylinder with one end sealed, 12 is a cylinder located inside the outer cylinder 11 and forms a reservoir chamber 13 for hydraulic oil between the inner surface of the outer cylinder 1, and 14 is a cylinder 14 on one end side of the cylinder 12. provided, the reservoir chamber 13 and the cylinder 12
The bottom valve 14 includes a bottom body 15 having an annular protrusion 15a, and is placed on the protrusion 15a of the bottom body 15, and is a bottom pulp that allows limited flow of hydraulic oil between the inside 12a and the bottom valve 14. an annular valve plate (16) serving as a damping force generating means having an orifice (16a) and a central opening (161); a check body (17) placed on the valve plate (16) and having upper and lower communication holes (17a); 16 and the check body 17 so as to be slidable in the axial direction, and the upper and lower communication holes 18
A check spring 19 is provided within the retainer 18 and biases the check body 17 toward the valve plate 16 with a small spring force.

20 is a piston rod that extends sealingly through the other end (not shown) of the cylinder 12;
A piston pulp 21 is provided at one end of the cylinder 12, and a slidable piston 24 is fixed to the interior 12a of the cylinder 12, separating upper and lower oil chambers 22 and 23K.

The piston pulp 21 includes a piston body 25 having an annular protrusion 25a and upper and lower communication holes 251), and is placed on the protrusion 25a of the piston body 25, and has a metering orifice 26a and a central opening 26'b. A valve plate 26 serving as a damping force generating means, a check body 27 placed on the valve plate 26, and an upper and lower communication hole 28 that slidably accommodate the valve plate 26 and check body 27 in the axial direction. a, and a check spring that is located inside the retainer 28 and biases the check body 27 toward the valve plate 26 with a small spring force. Further, the bottom pulp 14 includes a spiral bimetal (material), a control plate 31 to which the ends of the bimetal 30 are operatively connected, and the control plate 31 whose opening and closing are controlled by the control plate 31. An orifice 32 is attached to create a flow between the oil chambers that does not act on the pulp plate 16, which is a damping force generating means, and these bimetallic 3
0, the control plate 31, and the orifice 32 constitute a temperature compensation mechanism. The above is Ino. The barrel 30 is accommodated in four parts 171) recessed in the upper surface of the check body 17, and the outer end 30a of the bimetal 30
As shown in FIGS. 6 and 7, the check body 17
The inner end 30b of the check body 17 is fitted into the recess 171) provided on the outer periphery of the recess 17c.
It is fitted and locked to a ring) 17f of a shaft 17e, which is rotatably fitted into a hole 17α provided in the center shaft. The control plate 31 is attached to the shaft 17e while being placed on the bottom surface of the recess 171). Therefore, the control plate 31 and the check body 17 are rotated relative to each other via the bimetal 30 which responds to changes in the temperature of the hydraulic oil, and the control plate 31 can control opening and closing of the opening end of the orifice 32. It is. 17g is a stopper that stops the rotation of the control plate outside the set temperature range based on the design standard; 33 is the shaft 17;
17. A cross-shaped washer 34 is rotatably inserted through the check body 17 and placed on the upper surface of the check body 17 to receive the lower end of the check spring. This is a stopper plate that is caulked to the upper end of e and prevents the cross-shaped washer 33 and the like from coming off.

Such a hydraulic shock absorber is mounted and used by fixing the upper end of the piston rod 20 onto the spring of the vehicle and the lower end of the outer cylinder 11 below the spring, as in the conventional example. . First, FIG. 7 shows a normal temperature state where the temperature of the hydraulic oil is about 23° C., and the orifice 32 for oil temperature compensation is maintained in a closed state by the control plate 31. Therefore, when the piston rod 20 and the piston 24 move upward in such a state, the upper oil chamber 22 becomes high pressure, and when the rising speed of the piston 24 is small, the hydraulic oil in the upper oil chamber 22 flows into the retainer 28 of the piston valve 21. Notch 28a.

The oil chamber 23 in the lower part is gradually lowered through the hole 27a1 of the check body 27, the metering orifice 26a of the pulp plate 26, which is a damping force generating means, the central opening 26b1, and the communication hole 251 of the bottle body 25). As the rising speed of the piston 24 increases, the pressure in the upper oil chamber 22 becomes higher and higher, and finally the inner peripheral part of the pulp plate 26, which is a damping force generating means, is bent downward, and the The hydraulic oil in the oil chamber 22 passes through the metering orifice 26a and the central opening 26b of the pulp plate 26 and flows into the lower oil chamber 23 with a pressure drop.

In this case, the valve play which is a damping force generating means) 16
Specifically, the damping force is obtained by utilizing the metering orifice 16a of this and the energy loss when it bends and passes through this pulp plate 16. At the same time,
The hydraulic oil in the reservoir chamber 13 easily pushes up the pulp plate 16 and check body 17 of the bottom pulp 14 against the weak spring force of the check spring 19 in order to compensate for the withdrawal volume of the piston rod 20. The pulp is introduced into the cylinder 12 through a gap formed between the annular projection 15a of the body 15 and the pulp plate 16.

On the other hand, when the piston rod 20 moves downward together with the piston 24, the volume of the lower oil chamber 23 is reduced, and the oil chamber 23 is reduced in volume.
The hydraulic oil in the piston pulp 21 and the check body 27 are connected to the check spring 2.
It is pushed up against the weak spring force of 8, and flows into the upper oil chamber 22 through the gap created between the annular projection 25a of the piston body 25 and the pulp plate 26. At the same time, K
Cylinder 1 corresponding to the penetration volume of the piston rod 20
Similarly to the operation of the piston valve 21 when the piston rod 20 moves upward, the hydraulic oil in the valve plate 16, which is a damping force generating means, is flexed, specifically, its metering orifice 16a and this. It flows into the reservoir chamber 13 through this valve plate 16 and obtains a damping force.

In other words, when the piston rod 20 moves upward, the piston valve 21 obtains a damping force, and when the piston rod 20 moves downward, the damping force is obtained from the bottom pulp 1.
4 obtains a damping force, and during downward movement, the bottom pulp 14 obtains a damping force, and this damping force is generated by the orifice 32.
In the closed state, the total amount of fluid displacing and flowing through each oil chamber 13, 22 and 23 as the piston rod 20 moves up and down affects the piston valve 21 or the damping force generating means 16, 26 of the bottom pulp 14. By passing through, the desired value is obtained.

Next, when the temperature of the hydraulic oil is low, such as immediately after starting driving in a cold region, the bimetal 3
0, the control plate 31 and check body 17 rotate relative to each other (the control plate rotates counterclockwise in FIG. 7), and the control plate 31 opens the orifice 32 for oil temperature compensation. Therefore,
At room temperature, the entire amount of hydraulic oil passes through the pulp plate 16 which is a damping force generating means of the bottom pulp 14, but a portion of the hydraulic oil bypasses the orifice 32. That is, when the oil temperature is low and the operating speed of the piston rod 20 is the same as when it is at room temperature, the amount of hydraulic oil that passes through the pulp plate 16, which is the damping force generating means, is the same as when the orifice 32 opens and passes through the pulp plate 16. It will be reduced by the amount. This suppresses an increase in damping force due to an increase in kinematic viscosity due to a decrease in the oil temperature of the hydraulic oil, making it possible to obtain substantially the same damping force at room temperature.

Control plate 31 due to increase in hydraulic oil temperature
The clockwise rotation in FIG. 7 is prevented by the stopper 17gK so that the control plate 31 does not deviate from a range in which the opening of the orifice 32 is maintained in a closed state.

In the first embodiment described above, the oil temperature compensation mechanism was attached only to the bottom pulp 14 side. This is because the damping force of ) has a large influence, and if necessary, it is also possible to attach an oil temperature compensation mechanism to the piston pulp 21 side.

FIGS. 8 and 9 are drawings of a hydraulic shock absorber according to a second embodiment in which an oil temperature compensating mechanism is attached to both the piston valve and the bottom pulp. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant explanation thereof will be omitted.

That is, the piston valve 21 has a spiral shaped metal 3.
5, a control plate 36 to which an end of the bimetal 35 is operatively connected, and the control plate 3
An orifice 38 is attached to create a flow between the oil chambers that does not act on the valve plate 26, which is a damping force generating means, and is controlled to open and close depending on the timing. The control plate 36 and orifice 38 constitute a temperature compensation mechanism. The orifice 38 is provided in a bimetal holder 37 that is fitted into the lower end cylindrical portion 25C of the piston body 25, and the bimetal 35 and the control plate 36 are formed on the upper surface of the bimetal holder 37.
It is accommodated in the recessed portion 37a. The outer end 35a of the spiral bimetal 35 is attached to the bimetal holder 3.
The inner end 35'b of the recess 3 of the bimetal holder 37 is fitted and locked to the inner end 35'b
Rotatably inserted into the hole 370 provided in the center of 7a,
The shaft 37 (1 (7) sulin) 37e is fitted and locked, and the control plate 36 is attached to the shirt 37 (1) with the control plate 36 placed on the bottom surface of the recess 37a. The control plate 36 rotates relative to the bimetal holder 37 via a shaft 37 (1) by a bimetal 35 that responds to changes in the temperature of the hydraulic oil, and can control opening and closing of the opening end of the orifice 38. 37g is a stopper that stops the relative rotation of the control plate 36 outside the set temperature range as a design standard, and 39 is the shirt) 37 (1) is rotatably inserted and placed on the top surface of the bimetal holder 37. A cross-shaped washer 4o is caulked to the upper end of the shaft 37d, and a stopper plate 41 for preventing the cross-shaped washer 39 and the like from coming off is inserted into the lower end cylindrical portion 25C of the piston body 25. Bimetal holder 37
This is a retaining ring that prevents it from coming off. Further, the interior of the lower end cylindrical portion 25Q of the piston body 25 and the upper oil chamber 22 are connected by an oil passage.

Since the hydraulic shock absorber of the second embodiment has the configuration as described above,
Piston rod 20 detailed in the first embodiment
Similar to the operation of the oil temperature compensation mechanism attached to the bottom valve 14 when the oil temperature of the hydraulic oil moves downward, when the oil temperature of the hydraulic oil is low, the control plate 36 is relatively rotated by the bimetal 35 that responds to the oil temperature. open. Therefore, when the piston rod 20 moves upward, a part of the hydraulic oil flowing between the oil chambers 22 and 23 via the pulp plate 26 that uses the damping force generating means flows through the orifice 38 under the connection state through the oil passage 42. As a result, even when the piston rod 2 () moves upward, the increase in damping force due to the increase in kinematic viscosity due to the decrease in the oil temperature of the hydraulic oil is suppressed, and substantially the same damping force is obtained at room temperature. .

Therefore, according to this second embodiment, the piston rod 20
During both upward and downward movement, it is possible to suppress an increase in the damping force due to a drop in the temperature of the hydraulic oil, thereby further improving the ride comfort of the vehicle.

Also, bimetal 35. The control plate 36 and the orifice 38 are removably attached to the piston main body 25 constituting the piston pulp 21, or are provided in association with the bimetal holder 37, so that the bimetal 35. The control plate 36 and the like are constructed as one unit, and therefore can be attached to the piston pulp 21 conveniently.

However, in each of the embodiments shown in the drawings, when the oil temperature of the hydraulic oil drops below the set temperature, 1 orifice 32 for oil temperature compensation
, 38 is opened to lower the damping force. However, when the oil temperature of the hydraulic oil exceeds the set temperature, the orifice for oil temperature compensation is closed on the control plate and the hydraulic oil is lowered. It may also be used for so-called high temperature control, which suppresses a decrease in damping force due to a decrease in viscosity.

In addition, an orifice for oil temperature compensation is kept half open by a control plate at room temperature, and when the oil temperature decreases, the opening area of the orifice is increased, and when the oil temperature rises, the opening area of the orifice is decreased. If so, the oil temperature is high.

It becomes possible to control the damping force over both low temperature ranges.

Furthermore, although the orifice for oil temperature compensation is circular in each of the above embodiments, the opening shape of the orifice may be formed in a rectangular or fan shape to adjust the opening area of the orifice according to the viscosity characteristics of the hydraulic oil. By adjusting the damping force, the damping force can be controlled with higher precision. Further, the present invention is not limited to a dual-tube type hydraulic shock absorber.

As explained above, according to the present invention, one or both of the piston pulp and the bottom valve are provided with a damping force generating means opposite to one open end of the communication hole that communicates between the oil chambers. An orifice is provided that acts on the damping force generating means and creates a flow between the oil chambers, and a control plate is attached to one open end of the orifice to which an end of a bimetallic spiral is operatively connected. B. Since the control plate and the orifice are rotated relative to each other by a bimetal that responds to changes in oil temperature, the opening area of the orifice is changed, so the amount of deformation of the bimetal in response to changes in oil temperature. In addition, the control plate can control the opening and closing of the orifice over a wide range from fully open to fully closed, making it possible to keep the damping force constant over a wide temperature range. A hydraulic shock absorber can be obtained, and this effect can be obtained more advantageously by making the opening shape of the orifice elongated in the direction of relative displacement with the control plate based on the large amount of deformation of the bimetal. In addition, since the bimetal can be made smaller in the diameter direction, the installation space can be reduced, and the oil level compensation mechanism consisting of the bimetal, control plate, etc. can be attached to each valve as a single unit. This has the effect that the installation work can be done easily.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the temperature and kinematic viscosity of hydraulic oil, Figure 2 is a sectional view of a conventional hydraulic shock absorber with an oil temperature compensation mechanism, and Figure 3 is a diagram showing the relationship between the oil temperature and kinematic viscosity of hydraulic oil.
Figures a and ) are also plan views of the main parts, Figure 4 is a plan view of the main parts of a hydraulic shock absorber using a U-shaped bimetal, Figure 5 is a sectional view showing the first embodiment of the present invention, and Figure 6 is a plan view of the main parts. The figure is V in Figure 5.
A cross-sectional view taken along the I-Vl line, Figure 7 is a cross-sectional view taken along the ■-■ line in Figure 5,
FIG. 8 is a sectional view showing a second embodiment of the present invention, and FIG. 9 is a sectional view taken along the line IX--IX in FIG. 12-・Cylinder, 1311・Fist reservoir chamber (oil chamber),
14-1I bottom pulp, 150 bottom body, 1
6...Pulp plate (damping force generating means), 17.
...Checked body, 17e...Shaft, 20...
・Piston pulp, 21...Piston pulp, 22
, 23...-oil chamber, 25 fight/Φ piston body, 2611
... Valve plate (damping force generation means), 30, 35
0...Bimetal, 31, 36---Control plate, 32, 3R@...Orifice, 37...Bimetal holder, 37aIII111 four parts, 37dΦ・
-Shaft. 186- JP 59-231232 (11)

Claims (4)

[Claims] (1) Either or both of the piston valve and the bottom valve, which are provided with a damping force generating means opposite to one open end of the communication hole that communicates between the oil chambers, does not act on the damping force generating means; An orifice is provided to create a flow between oil chambers, and a control plate is attached to one open end of this orifice to which a spiral bimetallic end is operatively connected.The bimetallic plate responds to changes in oil temperature. A hydraulic shock absorber with an oil temperature compensation mechanism, characterized in that the opening area of the orifice is changed by relatively rotating the control plate and the orifice. (2) The orifice is provided in a bimetal holder attached to a piston body constituting a piston valve, and the control plate is fixed to a shaft supported approximately at the center of the bimetal holder, and the control plate is attached to the inner circumference of the bimetal. A hydraulic shock absorber with an oil temperature compensation mechanism according to claim 1, wherein the ends are connected. (3) The oriice is provided on a check body that is placed on the bottom body with the damping force generating means in between and constitutes the bottom valve, and the control plate is provided on a shaft that is supported approximately at the center of the check body. A hydraulic shock absorber with an oil temperature compensation mechanism according to claim 1, wherein the inner peripheral end of the bimetal is connected to the shaft. (4) The orifice is provided in a bimetal holder attached to the piston body that constitutes the piston pulp,
The control plate is fixed to a shaft supported approximately at the center of the bimetal holder, and the bimetal is housed in a recess provided in the bimetal holder so that its outer peripheral end is connected to the bimetal holder and its inner peripheral end is connected to the shaft. The oil temperature control system according to claims 1 and 2, wherein the bimetal holder, control plate, shaft, and hypermetal are configured to be removably attached to the piston body as one unit. Hydraulic shock absorber with compensation mechanism.