JPH10184609A - Cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop the strength by eliminating the need for aligning the fitting position of a bracket and of a valve body, and to easily heighten coaxial precision by improving workability and assembling properties, and to ensure the stability of a body by preventing a piston rod from being actuated when an open/close valve is closed to supply oil even in such a state that the oil leaks, or that the air is separated in the oil. SOLUTION: This cylinder device has a cylinder tube 1, a bracket 16 provided on the end of the cylinder tube 1, and a valve body B provided in the outside trunk part of the cylinder tube 1. Both sides piston rods 3 and 4 of a piston 2 are movably inserted into the cylinder tube 1 through the piston 2, which defines two oil chambers 5 and 6 in the cylinder tube 1. In the valve body B, a bypass 7 communicates with the two oil chambers 5 and 6, and an accumulator 12 is provided for supplying oil to the oil chambers 5 and 6, and to a valve mechanism which opens and closes the bypass 7. In this case, the cylinder tube 1, the bracket 16 and the valve body B are integrally molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder device suitable for use with, for example, a rear wheel suspension of a reach type forklift truck.

[0002]

2. Description of the Related Art As a cylinder device used for a rear wheel suspension of a reach type forklift truck, for example, a cylinder device disclosed in JP-A-6-191250 is known. In this cylinder device, piston rods on both sides of the piston are movably inserted into a cylinder tube via a piston, two oil chambers are defined in the cylinder tube, and the two oil chambers are connected via a bypass outside the cylinder tube. In the middle of the bypass, an electromagnetic on-off valve is provided to be openable and closable, the two piston rods are respectively connected to the body frame and the link mechanism, and the on-off valve is controlled by signals from a vehicle speed sensor and a tilt acceleration sensor. It is made to be done. In this case, when the cylinder tube and the cylinder tube side are connected to the vehicle body, the bracket and the bracket are separately molded and assembled, and the valve body forming the bypass is separately molded and assembled with the cylinder tube. Further, in this cylinder device, during normal running of the forklift truck, the on-off valve is opened so that the piston rod can be operated, so that the suspension spring provided in the link mechanism is operated to absorb vibrations and the like. On the other hand, at the time of cargo handling work at high elevation, at low speed, or when turning sharply, the on-off valve is closed by a signal from the vehicle speed sensor or the tilt acceleration sensor, and the movement of the piston rod is locked to prevent the suspension spring from operating. To stabilize the vehicle body.

[0003]

However, in the above-described cylinder device, since the cylinder tube, the bracket, and the valve body are separately molded and assembled to each other, it is difficult to process the cylinder device. The work is troublesome, it is difficult to achieve the coaxial accuracy between the cylinder tube side and the piston rod side at the time of assembly, and the cylinder tube and the bracket are screwed together so that the bracket and the valve body can be moved around the cylinder axis. Alignment is difficult. In addition, when the above cylinder device is used, the oil in the cylinder tube leaks from the seal provided on the bearing that guides the piston rod, or when the air in the oil is classified as oil, the on-off valve closes. The piston rod can move as much as the oil leaks even if the oil is leaking, or the piston rod can move as much as the compressed air separated, and the body of the vehicle body can be moved during cargo handling work at high elevation or sudden turning. Stabilization may not be achieved.

Therefore, an object of the present invention is to prevent oil leakage,
Even if the air in the oil separates, replenish the oil and the piston rod does not operate when the on-off valve is closed, stabilizing the vehicle body,
Furthermore, processability and assemblability are improved, and coaxial accuracy is easily obtained.
An object of the present invention is to provide a cylinder device that does not require positioning of a mounting position of a bracket and a valve body, and can increase strength.

[0005]

According to a first aspect of the present invention, a cylinder tube, a bracket provided at an end of the cylinder tube, and an outer body of the cylinder tube are provided. A piston body is movably inserted into the cylinder tube through a piston through a piston, the piston partitions two oil chambers in the cylinder tube, and the valve body has two oil chambers. And a valve mechanism for opening and closing the bypass and an accumulator for supplying oil to the oil chamber, wherein the cylinder tube, the bracket, and the valve body are integrally formed. It is.

Similarly, a second configuration has a cylinder tube, a bracket provided at an end of the cylinder tube, and a valve body provided at an outer trunk of the cylinder tube. The piston rods on both sides of the piston are movably inserted, the piston partitions two oil chambers in the cylinder tube, and the two oil chambers communicate via a bypass. In a cylinder device provided with an orifice in series with a valve, an accumulator is connected to a bypass via a check valve, and in the valve body, the bypass, an on-off valve, an orifice, a check valve, and an accumulator are provided. The cylinder tube, bracket and valve body are integrally molded. That. In this case, it is preferable that the piston and the piston rod are integrally formed.

[0007] Similarly, it is preferable that a conical chamfer is formed on the outer periphery of the end of the piston.

Similarly, the seal housing is press-fitted or screwed into the inner peripheral end of the bracket in a cartridge type with the seal previously incorporated in the inner periphery of the seal housing, and the piston rod slides on the inner periphery of the seal. Preferably.

In this case, it is preferable that the end of the seal housing protrudes toward the oil chamber.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. As shown in the circuit diagram of FIG.
The piston rods 3, 4 on both sides of the piston 2 are movably inserted through the piston 2, and the piston 2 is
The two oil chambers 5 and 6 are divided into two on the left and right.
Is communicated via an external bypass 7 connected to the cylinder tube 1, an opening / closing valve 8 is provided in the bypass 7 so as to be openable and closable, and an orifice 9 is connected in series with the opening / closing valve 8 in the middle of the bypass 7. In addition, an accumulator 12 is connected to the bypass 7 via a check valve 10 and an oil passage 11.

In this case, the two oil chambers 5, 6 in the cylinder tube 1 are connected via an auxiliary oil passage 13 parallel to the bypass 7.
4 are provided.

The present invention will be described in more detail with reference to FIG.

The cylinder device A includes a cylinder tube 1
And a bracket 16 integrally connected to one end of the cylinder tube 1 and a valve body B integrally formed outside the body of the cylinder tube 1.

The cylinder tube 1 and the bracket 16 are hollow and integrally formed. A cap 15 is connected to one end of the cylinder tube 1 with a screw or the like, and a seal housing 40 with a seal attached to the inner peripheral end of the bracket 16. Are press-fitted or screwed in a cartridge type.

The piston rods 3 and 4 on both sides of the piston are movably inserted into the cylinder tube 1 and the bracket 16 via the piston 2. The piston 2 and the piston rods 3 and 4 are integrally formed. One piston rod 3 slides on the oil seal a and the dust seal b in the seal housing 40, and the other piston rod 4 has the oil seal c in the cap 15. The dust seal d is sliding.

A conical chamfer 2a is formed on the outer periphery of the end of the piston 2 so as to secure an oil passage for the bypass 7, as will be described later. One end of the seal housing 40 slightly protrudes from the end face of the bracket 16 toward the oil chamber 6 to secure an oil passage for the bypass 7 as described later. The hollow portion 17 in the bracket 16 is open to the outside via a through hole and a filter 16b.

A valve body B is integrally provided outside the body of the cylinder tube 1, and a bypass 7 is provided in the valve body B to communicate the two oil chambers 5 and 6 in the cylinder tube 1. Orifice 9 on the way,
An on-off valve 8 composed of an electromagnetic valve for selectively opening and closing the bypass 7 and an accumulator 12 connected via a check valve 10 to an oil passage 11 branched from the bypass 7 are provided. Further, the bypass 7 is provided with an auxiliary oil passage 13 that bypasses the opening / closing valve 8.
4 and two oil chambers 5 regardless of the open / close valve 8
6 can be disconnected. The opening and closing valve 8 is controlled to open and close by signals from a vehicle speed sensor and a tilt acceleration sensor of the vehicle.

One piston rod 4 is connected to, for example, the body side of a reach type forklift truck via a bracket 4a at an end, and a bracket 16 is connected to an eye 16a.
Is connected to the wheel side link mechanism. However, one piston rod 4 is connected to the vehicle body side, and the bracket 1
6 may be connected to a link mechanism. In this case, a suspension spring is interposed between the vehicle body and the link mechanism in parallel with the cylinder device A of the present invention, so that the cylinder device A can operate.
In other words, when the open / close valve 8 in the bypass 7 is open, the suspension spring operates to absorb vibrations and the like against the running vehicle body, but when the open / close valve 8 is closed and the cylinder device A is locked. The suspension spring also does not operate, and for example, when the vehicle is stopped, the vehicle body is stabilized without vibrating up and down.

The bypass 7 formed in the valve body 13 is composed of ports 18 and 19 that open to the two oil chambers 5 and 6 and an oil passage 22 that communicates with each of the ports 18 and 19. The open / close valve 8 is bypassed between the ports 18 and 19 in parallel with the path 22.

The on-off valve 8 composed of an electromagnetic valve includes a solenoid S, an iron core 24 movably provided at the center of the solenoid S via a guide 25, a hollow sleeve 26, and a hollow portion serving as a passage in the sleeve 26. 27, a poppet type valve element 31 which is movably disposed via a guide 29 and is in contact with the iron core 24.

At the end of the sleeve 26, a spring seat 32 having a port 28 is disposed. A spring 33 interposed between the spring seat 32 and the valve body 31 keeps the valve body 31 in the sleeve state. The sheet 26 is pressed against the sheet surface and urged in the closing direction. The sleeve 26 has an orifice 9 opening to the oil passage 22.

The hollow part 2 constituting a part of the bypass 7
A hollow housing 34 is provided in the housing 0, and the accumulator 12 and the check valve 10 are incorporated in the housing 34.

The accumulator 12 includes an oil chamber 35 provided in a housing 34, a free piston 36 movably fitted in the housing 34, and air or gas formed in a body 41 opposed to the free piston 36. And a gas chamber 37 composed of The gas chamber 37 may be made of an elastic body such as a coil spring or rubber.

The housing 34 is formed with an oil passage 11 and a hollow portion communicating with the hollow portion 20 serving as the bypass 7 of the oil chamber 35, and a valve body 31 for opening and closing the oil passage 11 is formed in the hollow portion.
A check valve 10 comprising a spring for biasing the valve element 31 in the closing direction is provided. When the check valve 10 opens the oil passage 11, the oil chamber 35 constituting the accumulator 12 communicates with the hollow portion 20, and the oil in the oil chamber 35 is transferred to the hollow portion 2.
0 and the oil chamber 5 in the cylinder tube 1 through the port 18
Is to be replenished.

Signals from a vehicle speed sensor and a tilt acceleration sensor provided on the vehicle body side are applied to the solenoid S via lead wires, and are excited by the respective signals to open the valve body 31. That is, a signal is not input when a cargo operation is performed at a high elevation, when the vehicle is traveling at a low speed, or when the vehicle makes a sharp turn while traveling, whereby the valve element 31 constituting the open / close valve 8 is closed by the spring 33. I have. On the other hand, when the vehicle is traveling normally, a signal from the vehicle speed sensor is applied to the solenoid to excite it. Therefore, the iron core 24 is sucked and the valve body 31 is opened against the spring 33.

Next, the operation will be described. When carrying out cargo handling work at low speed or at high elevation, the solenoid S
Is not excited, whereby the opening / closing valve 8 is at the right position in FIG. 1 and the valve element 31 closes the bypass 7. When the vehicle turns sharply, the excitation of the solenoid S is stopped by a signal from the tilt acceleration sensor, and the opening / closing valve 8 is closed. Therefore, no oil flows from the bypass 7, the piston rods 3, 4 do not operate, and the cylinder device A is locked.
Accordingly, the link mechanism is also locked because the suspension spring does not move, so that the vehicle body does not move up and down, thereby stabilizing the vehicle body.

On the other hand, when the vehicle normally travels, the solenoid S is excited by a signal from the vehicle speed sensor, the valve 31 is opened, and the open / close valve 8 is switched to the left position in FIG. 6 communicates via a bypass 7 to enable the piston rods 3 and 4 to operate, whereby the suspension spring operates to absorb vibrations on the vehicle body and improve ride comfort. When the oil flows through the bypass 7 when the piston rods 3 and 4 are operated, the oil is throttled by the orifice 9 to attenuate a sudden impact on the vehicle body.

For example, in FIG. 1, when the piston 2 moves to the right when the valve element 31 is open, the oil in one of the oil chambers 6 is discharged from the port 19, the port 28, the hollow portion 27, the orifice 9 and the oil passage 22. The oil flows into the other oil chamber 5 through the hollow portion 20 and the port 18, and at this time, a damping force is generated in the orifice 9. At this time, even if the piston 2 strokes to the right as much as possible, the right end face of the piston 2 abuts the left end of the seal housing 40, and a gap corresponding to the protrusion of the end of the seal housing 40 is secured, and the oil passage to the port 19 is formed. Can be secured. Similarly, even if the piston 2 moves to the left and abuts the cap 15, the chamfer 2a is formed, so that the oil passage of the port 18 is secured.

If the opening / closing valve 8 cannot be opened for any reason during such operation, the stop valve 14 is manually opened and the two oil chambers 5 and 6 are communicated via the auxiliary oil passage 13.

If oil leaks from a seal for guiding the piston rod 4 or a seal interposed between the cylinder tube 1 and the cap 15 and the bracket 16 during use for a long time, or if air mixed in the oil is leaked. When separated from the oil, the opening / closing valve 8 for the amount of oil leakage or air compression
Even if is closed, the piston rods 3 and 4 become slightly operable, and the vehicle body may be fluffy and in an unstable state. However, in the case of the present invention, this problem can be prevented.

That is, as shown in FIG. 1, when the piston rods 3 and 4 are operated in a state where the oil is leaked, the oil chamber 5 or 6 is in a negative pressure state. The piston 36 checks the oil in the oil chamber 35 with the check valve 10.
Is pushed open to supply oil from the hollow portion 20 to one of the oil chambers 5, so that the piston rods 3 and 4 are always locked to stabilize the vehicle body.

[0032]

According to the present invention, the following effects can be obtained.

According to the invention of each claim, since the cylinder tube, the bracket and the valve body are integrally formed, the inside of the cylinder tube and the inside of the bracket can be machined from the same direction, and the internal seal housing, cap, and piston rod can be machined. Etc. can be assembled from the same direction, and workability and assemblability are improved. Similarly, since there is no connection between the cylinder tube, the bracket and the valve body, the strength is increased, and the relative positioning work of the bracket and the valve body around the cylinder axis is unnecessary. Similarly, since the cylinder tube and the bracket are coaxially integrated, the axis of the cylinder tube and the guide member of the internal piston rod,
For example, the axes of the cap and the seal housing can be reliably set coaxially.

According to the invention of each claim, since the oil chamber is provided with the accumulator for replenishing the oil, the oil in the cylinder tube may partially leak or the air in the oil may be separated from the oil. When this happens, oil can be automatically supplied from the accumulator, whereby the piston rod can be locked when the open / close valve is always closed, and the vehicle body can be stabilized without fluffing. Therefore, fluctuations of the vehicle body can be prevented and stability can be achieved during cargo handling work at a high elevation, during low-speed running, or during a sharp turn.

According to the third aspect of the present invention, in addition to the above effects, even when the on-off valve is opened and the piston rod is operated, the orifice is provided in the bypass, so that even if a sudden impact acts on the vehicle body. The orifice attenuates this impact.

According to the third aspect of the present invention, since the piston and the piston rod are integrally formed, the strength of the piston and the piston rod can be increased, the workability and the assembling property can be improved, and the shaft cores of both can be improved. Can be secured coaxially.

According to the fourth aspect of the present invention, since the piston is chamfered, an oil passage for bypass can be secured even if the piston has a maximum stroke.

According to the fifth aspect of the present invention, since the seal housing and the seal are assembled in the form of a cartridge, the assemblability is improved, the seal is prevented from being damaged, and oil leakage can be prevented. Furthermore, since the seal housing projects toward the oil chamber, even when the piston has reached the maximum stroke,
This piston hits the seal housing, and a bypass oil passage can be secured by the gap of the protrusion of the seal housing.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a cylinder device according to the present invention.

FIG. 2 is a hydraulic circuit diagram of the cylinder device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder tube 2 Piston 3, 4 Piston rod 5, 6 Oil chamber 7 Bypass 8 Opening / closing valve 9 Orifice 10 Check valve 12 Accumulator 13 Auxiliary oil passage 14 Stop valve 16 Bracket B Valve body

Claims (6)

[Claims] 1. A cylinder tube, a bracket provided at an end of the cylinder tube, and a valve body provided at an outer body of the cylinder tube. Is movably inserted, the piston divides two oil chambers in the cylinder tube, and the valve body supplies a bypass connecting the two oil chambers, a valve mechanism that opens and closes the bypass, and supplies oil to the oil chambers. A cylinder device provided with an accumulator, wherein the cylinder tube, the bracket, and the valve body are integrally formed. 2. A cylinder tube, a bracket provided at an end of the cylinder tube, and a valve body provided at an outer body of the cylinder tube. Is movably inserted, the piston divides two oil chambers in the cylinder tube, and the two oil chambers communicate with each other via a bypass, and an on-off valve and an orifice in series with the on-off valve are provided in the middle of the bypass. In the cylinder device, furthermore, an accumulator is connected to the bypass via a check valve, and the bypass, the opening / closing valve, the orifice, the check valve, and the accumulator are provided in the valve body. A cylinder device characterized by being integrally formed with a body. 3. The cylinder device according to claim 1, wherein the piston and the piston rod are integrally formed. 4. The cylinder device according to claim 1, wherein a conical chamfer is formed on an outer periphery of an end of the piston. 5. The seal housing is press-fitted or screwed into the inner peripheral end of the bracket in a cartridge type with the pre-sealed seal incorporated in the inner periphery of the seal housing, and a piston rod slides on the inner periphery of the seal. 5. The cylinder device according to claim 1,2,3 or 4, which is moving. 6. The cylinder device according to claim 5, wherein an end of the seal housing protrudes toward the oil chamber.