JPS59217005A - Triple piston-cylinder apparatus - Google Patents

Abstract

PURPOSE:To locate a piston rod surely at four positions by receiving triple pistons in a cylinder in a relatively displaceable condition. CONSTITUTION:An outer piston 3 is displaceably housed in a cylinder 2, and a compression spring 6 is provided between an end of the cylinder 2 and an end of the outer piston 3. A stopper 12 is mounted on the inner periphery of the outer piston 3. In the outer piston 3, first and second intermediate pistons 4a and 4b are displaceably housed so as to be located on both sides of the stopper 12. An inner piston 5 is displaceably housed in the first and second intermediate pistons 4a and 4b. Accordingly, fluid supplied from fluid feed ports P1, P2, and P3 is suitably selected, thereby the piston rod 5 being capable to be surely located on four positions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies a pressing force by an elastic body to a triple piston cylinder system & KQ cylinder, especially when the force for displacing the piston rod becomes small in relation to the pressure receiving area.
The present invention relates to a cylinder device in which the force for displacing the piston rod is equalized and the piston rod can be set at four predetermined positions with a simple configuration.

In a conventional single piston cylinder device, the piston rod fixed to the piston can be reliably set at two points, but it is possible to set the piston rod fixed to the piston at two points, but it is possible to set the piston rod at two points plus two intermediate points, such as a transmission. The disadvantage was that it was not possible to reliably set the four points required for automatic gear shifting operations, etc.

The present invention has been made to eliminate the drawbacks of the prior art described above, and its purpose is to provide a simple structure by accommodating a triple piston in a cylinder so that it can be relatively displaced. To enable a piston rod to be reliably set at four points. Another object is to enable a single cylinder device to perform a selection operation for a transmission having four selection positions. Still another purpose is to equalize the force that displaces the piston rod by adding the spring force of the compression spring when the force that displaces the piston rod is particularly small in relation to the pressure receiving area. It is also an object of the present invention to provide a compact and lightweight cylinder device that eliminates the need to increase the dimensions of the piston rod and its related parts.

In summary, the present invention comprises a cylinder, a hollow outer piston slidably housed within the hollow portion of the cylinder, and first and second intermediate pistons slidably housed within the outer piston. an inner piston integrally formed with an intermediate piston and a piston rod that is slidably housed within the intermediate piston, passes through one end of the second intermediate piston, and slidably passes through one end of the cylinder; a first fluid boat for displacing the outer piston by a maximum amount toward the piston rod; a second fluid boat communicating with the hollow portion of the outer piston to displace the first intermediate piston by a maximum amount toward the piston rod within the outer piston; and the outer piston, the intermediate piston, and the inner piston. a third fluid boat for displacing the piston rod by a maximum amount to the opposite side of the piston rod, and the piston rod is moved to a predetermined four-point position by relative displacement of the outer piston, the intermediate piston, and the inner piston. The outer piston is configured such that when it is displaced by the maximum amount to the opposite side of the piston rod, the outer piston is displaced by applying a pressing force by the elastic body to the piston rod side. It is.

The present invention will be explained below based on embodiments shown in the drawings. The triple piston cylinder device 1 according to the present invention includes a cylinder 2, an outer piston 3, an intermediate piston 4 consisting of first and second intermediate pistons 4a14b, an inner piston 5, and a compression spring formed in a line of an elastic body. 6.

The cylinder 2 has a sealed structure, and has a hole 2b at the right end 2a in the figure through which a piston rod 5a integrally formed with the inner piston 5 is slidably penetrated via a seal member 8. is formed.

The cylinder 2 also connects the outer piston 3 to the piston rod 5.
A first fluid boat Pl communicates with the hollow portion 3a of the outer piston 3 to displace the first intermediate piston 4a by the maximum amount toward the piston rod 5a side within the outer piston 3. 2 fluid boat P! and a third fluid boat P for displacing the outer piston 3, the second intermediate piston 4b, and the inner piston 5 by the maximum amount to the opposite side of the piston rod 5a. Each of these fluid boats is connected to a fluid supply source (not shown) such as air or oil via a spool control valve (not shown), etc.
It is connected to the.

The outer piston 3 is slidably housed in the hollow part 2C of the cylinder 2 via a seal member 9, and is formed hollow, and the left end in the figure is sealed by a wall part 3b. A groove 3C communicating with the hollow portion 2C of the cylinder 2 is provided at the right end. Further, in the lower part of the outer piston 3 in the figure, there is a groove 3d that communicates the second fluid boat P1 and the hollow part 3a, and a communication hole 3e that communicates with the ridge groove and the hollow part 3a, and in the lower part of the cylinder 20 in the figure. Formed discharge hole 2
A groove 3g communicating with the groove e is provided respectively.

The outer piston 3 is capable of sliding left and right inside the cylinder 2 within a range including the stroke.

The first intermediate piston 4a is slidably housed in the outer piston 3 via a sealing member 10, and is formed hollow, with a wall 4C formed at the left end in the figure. , a hole 4d that communicates with the hollow part 3aK of the outer piston 3.
is formed.

Further, the first intermediate piston 4a has an open end 4e formed at the right end in the figure that comes into contact with a stopper 12 embedded in the middle part of the inner circumferential surface of the outer piston 3, so that its stroke
Shoes 2 are now regulated. And straw
It is designed to be able to slide left and right within the outer piston 3 within the range of the shoes 2.

The second intermediate piston 4b is slidably housed in the outer piston 3 via a seal member 13, and is formed in the same shape as the first intermediate piston 4a, and is located at the right end in the figure. A piston rod 5 is inserted into the hole 4g of the wall portion 4f.
a passes through.

Further, the stroke of the second intermediate piston 4b is restricted by the opening end 4h formed at the left end in the figure coming into contact with the stopper 12 of the outer piston 3. It can slide left and right within the outer piston 3 within a range of strokes 3.

The inner piston 5 includes first and second intermediate pistons 4a+
4b through a sealing member 15, and within the range of the sum of strokes 13 and 14, the single or second
It is designed to be able to slide left and right within the outer piston 3 along with an intermediate piston 4b, and a piston rod 5a is integrally formed on the right side.

The outer piston 3, the intermediate piston 4 which receives force from the first and second intermediate pistons 4a+4b, and the inner piston 5.
The piston rod 5a is configured to be able to be set at predetermined four-point positions QpQ* +Qs and Q4 according to the relative displacement between the piston rod 5a and the piston rod 5a.

The compression spring 6 is disposed in the hollow portion 2C of the cylinder 2, and its both ends are connected to recesses 2h and 3h formed in the left end 2g of the cylinder 2 and the wall 3b of the outer piston 3, respectively.
It is designed to be accommodated in The compression spring biases the outer piston 3 toward the piston rod 5a.

The present invention is constructed as described above, and its operation will be explained below. First, the case where the piston rod 5a is set to the rightmost first position Q1 will be explained with reference to FIG.

When fluid flows into the first fluid port P+ as shown by arrow B1, the outer piston 3 is displaced to the rightmost position and stops. At the same time, when fluid is allowed to flow into the second fluid port P2 as shown by arrow B2, the fluid flows into the hollow portion 3a through the groove 3d and the communication hole 3e, and then flows into the first intermediate rod 4a.
is displaced to a position where it hits the stopper 12 and stops, and the inner piston 5 is moved to the second intermediate piston 4b together with the second intermediate piston 4b.
The wall portion 4f of the piston moves to the rightmost position corresponding to the right end 2a of the cylinder 2 and stops.

As a result, both the outer piston 3 and the inner piston 5 are displaced to the rightmost end and stopped, and the piston rod 5a
is set at the first position Q1. Therefore, for example, this first
By selecting position Q, the transmission can shift to fifth or sixth gear.

Next, the case where the piston rod 5a is set to the intermediate second position Q2 will be explained with reference to FIG. While maintaining the state shown in FIG. 1, fluid is allowed to flow into the third fluid port P as shown by arrow B. In this case, the pressure P of the fluid flowing into the first and third fluid bows) R and P3 is assumed to be the same, the cross-sectional area of the hollow portion 2C of the cylinder 2 is A1, the cross-sectional area of the piston rod 5a is the compression spring If the spring force of 6 is f, then
The force F that presses the outer piston 3 in the right direction in the figure is F,
=PA, -1-f, whereas the outer piston 3
The force F2 that presses to the left in the figure is F! =P(A, -A
4)=PA, -PA! Adashi, force F, is force F, more PA
, +f is larger by the amount added to it.

Therefore, the outer piston 3 stops, and the second intermediate piston 4b moves to the left, pushing the inner piston 5 to the left, until the second intermediate piston 4b hits the stopper 12. -12. Displaces to the left within the range of and stops. As a result, the piston rod 5 is changed from the state shown in FIG.
a moves to the left by stroke 13-no, and moves to the second
It is set at position Q2.

Therefore, when the second position Q2 is selected, the transmission can be shifted to the third or fourth gear.

Next, the case where the piston rod 5a is set to the intermediate third device Q will be explained with reference to FIG. When the supply of fluid from the second fluid port Pa is stopped while maintaining the state shown in FIG. Part 4C
stroke 1 until it hits the wall 3b of the outer piston 3.
Displaces to the left in the range of 2 and stops cooling. - As a result, the second
From the state shown in the figure, the piston rod 5a moves to the left by the right stroke and is set at the third position Q3. Therefore,
For example, by selecting the @3 position Q3, the transmission can be shifted to the first gear or the second gear.

Next, the case where the piston rod 5a is set to the leftmost fourth position Q4 will be explained with reference to FIG.

When the supply of fluid from the first fluid boat P1 is stopped while maintaining the state shown in FIG. 3, the outer piston 3 is displaced to the leftmost position until its wall portion 3b hits the left end 2g of the cylinder 2, and then stops. . At the same time, the inner piston 5 is also displaced to the left together with the outer piston 3, accompanied by the first intermediate piston 4a. As a result, the outer piston 3 and the inner piston 5
Both are displaced to the leftmost position and stopped, and the piston rod 5a is set at the fourth position Q4. Therefore,
For example, by selecting the fourth position tk:Q, the transmission can be shifted to reverse shift.

As described above, the piston rod 5a is reliably set at the four positions Q, , Q, tQs, and Q4 by fluid inflow control or outflow control.

Here, the force F that displaces the piston rod 5a when the piston rod 5a is displaced from &Q, , Q, , Q, , Q will be explained. Measure the diameter of the piston rod 5a, and set the diameter D□ of the inner piston 5 to mD6. intermediate piston 4
Let the diameter Dz of the outer piston 3 be ``Do+2nD@'' (m and 1m are constants).
, P, are all assumed to be the same, and the spring force of the compression spring 6 is assumed to be f.

And from the first position Q, to the second position Q! , the second position Q2
If the forces that displace the piston rod 5a when the piston rod 5a is displaced from the piston rod 5a to the third position Q3 and from the third position Q3 to the fourth position Q4 are respectively F +t, Fzs, and Fa4, then Fu = 7
((m+n arm mu-11D:P”=4 (m2-1
)Dir Fs4=7((m+2n)''-i)DIP-f.

Further, the forces that displace the piston rod 5a when the piston rod 5a is displaced from the fourth position Q4 to the third position Q3, from the third position Q3 to the second position Q2, and from the second position Q2 to the first device Q are respectively F4B j If f”3□, Fil, then F1a
=7D o P1f Fst=-t (m10n)"-m2+i) DIPF2
+ = -m" D: P. In the above equation, for example, m = 2. 'n = = 1 or m = 3
, n=1, the results are as shown in Table 1.

Table 1 As can be seen in Table 1, the pressure P in the case of F14
The coefficient of the pressure is 15 or 24, which is very large compared to other cases, whereas the coefficient of the pressure P when the force l is 43 is 0.2.
5, which is very small compared to the other cases, but in this case, the spring force f of the compression spring 6 is added to increase the force F4m. Further, the force F14 is reduced by the spring force f, but since the coefficient of the pressure P is very large, the decrease in the spring force f has almost no effect and can be ignored.

As described above, the piston rod 5a is moved from the fourth position Q4 to the third position.
When the force for displacing the piston rod is particularly small, such as when displacing the piston rod to position Qs, the spring force f is added by the compression spring 6 and increases, so that the force for displacing the piston rod 5a is evenly distributed. In particular, it is necessary to increase the diameter Do of the piston rod 5a. Therefore, the diameters of the inner piston 5, the intermediate piston 4, the outer piston 3, and the cylinder 2 also need to be particularly large, so that the cylinder device 1 becomes small and lightweight.

In the above embodiment, the elastic body 6 is described as a compression spring in the form of a coil spring, but instead of the compression spring, an air spring in the form of a bellows or a rubber material may be used. Alternatively, the end of the outer piston 3 on the piston rod 5a side may be pulled by a tension spring to bias the outer piston toward the piston rod 5a. Furthermore, in the above description, the fluid may be air or oil.

Since the present invention is configured and operates as described above, the triple piston is accommodated in the cylinder so that it can be relatively displaced, so the piston rod can be reliably positioned at four points with a simple configuration. There are 4 things that can be set.
The present invention has the advantage that the selection operation of a transmission having two selection positions can be performed with a single cylinder device, and can be applied to a wide range of other uses. Furthermore, since the spring force of the compression spring is added when the force for displacing the piston rod is particularly small in relation to the pressure receiving area, an effect is obtained in which the force for displacing the piston rod is equalized. In addition, as a result, there is no need to increase the dimensions of the piston rod and its related parts.
We can provide a small and lightweight cylinder device,
Extremely excellent effects can be obtained.

[Brief explanation of drawings]

The drawings relate to an embodiment of the present invention; FIG. 1 is a longitudinal cross-sectional view of a triple piston cylinder device in which the piston rod is set at the rightmost first position, and FIG. 2 is a vertical sectional view showing the piston rod in the middle position. A vertical cross-sectional view showing the case where it is set at the 2nd position,
FIG. 3 is a longitudinal sectional view showing the case where the piston rod is set at the third intermediate position, and FIG. 4 is a longitudinal sectional view showing the case where the piston rod is set at the leftmost fourth position. 1 is a triple piston cylinder device, 2 is a cylinder, 2
C is the hollow part of the cylinder, 3 is the outer piston, 3a is the hollow part of the outer piston, 4 is the intermediate piston, 4a is the first
, 4b is a second intermediate piston, 5 is an inner piston, 5a is a piston rod, 6 is a compression spring which is an example of an elastic body, P is a first fluid boat, P8 is a second fluid boat, P3 is the third fluid boat. Patent applicant Hino Motors Co., Ltd. Agent'
-Patent Attorney 1) Kazuo

Claims (1)

[Claims] an intermediate piston comprising a cylinder, a hollow outer piston slidably housed within the hollow portion of the cylinder, and first and second intermediate pistons slidably housed within the outer piston; an inner piston integrally formed with a piston rod that is slidably housed in the intermediate piston, passes through one end of the second intermediate piston, and slidably passes through one end of the cylinder; a first fluid boat for displacing the outer piston by a maximum amount toward the piston rod; a second fluid boat disposed in the hollow portion for displacing the first intermediate piston by a maximum amount toward the piston rod within the outer piston; and a third fluid boat for displacing the piston by a maximum amount to the opposite side, and the piston rond can be set at predetermined four-point positions by relative displacement of the outer piston, the intermediate piston, and the inner piston. The triple piston cylinder device is characterized in that the outer piston is displaced by applying a pressing force by the elastic body to the piston rod side when the outer piston is displaced by the maximum amount to the opposite side of the piston rod.