JP2003072570A - Power cylinder - Google Patents

Abstract

(57) [Problem] To provide a power cylinder capable of reducing a collision noise generated between a bush and a piston rod based on an external input. SOLUTION: A holder member 3 for holding a bush 4 includes:
The outer cylindrical portion 31 held in a press-fit state in the inner peripheral portion of the cylinder tube 1 by press-molding one metal plate material.
An inner cylindrical portion 32 for holding the bush 4 on the inner peripheral portion; a folded connection portion 33 provided to connect the inner cylindrical portion 32 and the outer cylindrical portion 31; Connection part 33
An outward flange 34 formed at the opening end opposite to the outside and formed outwardly at an opening end opposite to the connecting portion 33 of the inner cylindrical portion 32. An inward flange 35 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cylinder, and more particularly to an improvement in piston rod support structure.

[0002]

2. Description of the Related Art Conventionally, as a structure of a piston rod support portion in a power cylinder, for example, an actual flat blade 4-713 is used.
The one described in Japanese Patent No. 78 is known. In this conventional power cylinder, as shown in FIG. 6, the piston rod 104 is provided inside the end portion of the cylinder tube 101 outside the seal member 102 via the bush 103.
The holder member 105 for slidably supporting was made of a solid rigid body made of aluminum forged or cast.

[0003]

However, in general, in the power cylinder, since a minute gap is formed between the bush 103 and the piston rod, as in the conventional example, the holder member 105 is not provided. If the piston rod 104 is made of a rigid body and receives an external input, the bush 103 and the piston rod 1
There was a problem that 04 collided, and this caused abnormal noise. The present invention has been made in view of the above conventional problems, and provides a power cylinder capable of reducing a collision noise generated between a bush and a piston rod due to an external input. With the goal.

[0004]

In order to achieve the above-mentioned object, in a power cylinder according to claim 1 of the present invention, a cylinder tube and a holder fitted to an inner peripheral side end portion of the cylinder tube. A member, a bush held on the inner peripheral side of the holder member, a piston rod slidably held by the bush, and a hydraulic chamber provided in the piston tube and separated from the hydraulic chamber. In a power cylinder having a piston to be formed and a seal member provided inside the holder member in the axial direction and sealing between the cylinder tube and the piston rod, the holder member is formed by press-forming a plate material. The means to be

According to a second aspect of the present invention, there is provided the power cylinder according to the first aspect, wherein the bush is press-fitted and held in the inner peripheral portion of the holder member.

According to a third aspect of the present invention, there is provided the power cylinder according to the first or second aspect, wherein the outer peripheral portion of the holder member is formed with a bent outward flange portion that engages with the cylinder tube. did.

The power cylinder according to claim 4 is the power cylinder according to any one of claims 1 to 3.
The inward flange portion that prevents the axial movement of the bush is bent on the inner peripheral portion of the holder member.

A power cylinder according to claim 5 is the power cylinder according to any one of claims 1 to 4,
The power cylinder is used as a power cylinder of a power steering device that assists the steering force of the vehicle.

A power cylinder according to a sixth aspect is the power cylinder according to any one of the first to fifth aspects.
The holder member is provided in a state in which an outer tubular portion held on the inner peripheral portion of the cylinder tube, an inner tubular portion holding the bush, and a connection between the inner tubular portion and the outer tubular portion are connected to each other. The holder member is provided inside the cylinder tube and is configured to include a connecting portion that axially supports the seal member, and a surface of the connecting portion facing the seal member is a plane orthogonal to the axial direction of the cylinder tube. The part is formed.

A power cylinder according to a seventh aspect is the power cylinder according to any one of the first to sixth aspects,
A stopper member for restricting the movement of the tie rod is provided at the opening end portion of the cylinder tube, and the stopper member has the piston rod through hole at the center thereof and the outer peripheral edge side thereof is the opening of the cylinder tube. An annular stopper portion that is provided in a state of being locked to the end portion, and a fitting that extends from the outer peripheral edge portion of the stopper portion in the axial direction of the cylinder tube and is fitted to the outer periphery of the opening end portion of the cylinder tube. It is assumed that it is composed of a section and a section.

The power cylinder according to claim 8 is the power cylinder according to claim 7, wherein the inner peripheral surface of the piston rod through hole of the stopper portion of the stopper member is close to the outer peripheral surface of the piston rod. The means configured to regulate the swing of the piston rod by setting the inner diameter of the through hole.

The power cylinder according to claim 9 is the power cylinder according to any one of claims 3 to 8,
An annular step portion is formed inside the cylinder tube by forming a thin portion having an inner diameter larger than that of the other portion at the opening edge portion of the cylinder tube, and the outward flange of the holder member is formed on the annular step portion. The part is locked,
The thin portion is bent inward along the outer surface of the outward flange portion, and the outward flange portion is sandwiched and fixed between the bent thin portion and the annular step portion.

[0013]

In the power cylinder of the present invention, as described above,
Since the holder member is formed by pressing a plate material, the holder member has flexibility, and even when an external input in the radial direction acts on the piston rod, the impact between the piston rod and the bush is generated. It is absorbed by the flexibility of, and it becomes possible to reduce the collision noise.

In the power cylinder according to the second aspect, as described above, the bushes are press-fitted and held in the inner peripheral portion of the holder member, and thus the bushes and the holder member are formed with engaging and recessed portions for engaging and fixing. Without it, the bush can be held by the holder member.

In the power cylinder according to the third aspect, as described above, the outward flange portion bent and formed on the outer peripheral portion of the holder member is locked to the opening end portion of the cylinder tube or the like, so that the holder member Positioning and fixing can be performed easily.

In the power cylinder according to the present invention, as described above, the bush is positioned and fixed by bending the inward flange portion that prevents the axial movement of the bush in the inner peripheral portion of the holder member. Can be done easily.

According to the fifth aspect of the present invention, the power cylinder is used as the power cylinder of the power steering device for assisting the steering force of the vehicle, so that the impact between the piston rod and the bush due to the road surface input is applied to the holder. It is absorbed by the flexibility of the member, which reduces the collision noise and reduces the discomfort given to the driver.

In the power cylinder according to the sixth aspect, as described above, the holder member has an outer cylinder portion held by the inner peripheral portion of the cylinder tube, an inner cylinder portion holding the bush, and the inner cylinder. By being composed of the connecting portion provided in a state of connecting the portion and the outer tubular portion, it is possible to give sufficient flexibility to the inner tubular portion side with the connecting portion as a center. , It becomes possible to enhance the collision noise reduction effect. Further, a flat surface portion orthogonal to the axial direction of the cylinder tube is formed on a surface of the connection portion facing the seal member, so that the seal member is axially supported by the flat surface portion of the connection portion. As a result, the adhesiveness between the seal member and the flat surface portion increases, and the holding accuracy of the seal member improves.

In the power cylinder according to the seventh aspect, as described above, an annular stopper portion is provided at the open end of the cylinder tube, and the outer peripheral edge portion of the stopper portion extends in the axial direction of the cylinder tube. By providing the stopper member configured with the fitting portion that is fitted to the outer periphery of the opening end portion of the cylinder tube, the stopper function can be exerted with a simple configuration, and the fitting portion can be provided in the cylinder tube. By fitting it into the open end, the rigidity of the cylinder tube and holder member can be increased, and the step formed by the fitting is used as a step for locking when the boot cover is attached. become able to.

In the power cylinder according to the present invention, the inner diameter of the piston rod through hole is set so that the inner peripheral surface of the piston rod through hole of the stopper portion of the stopper member approaches the outer peripheral surface of the piston rod. With this configuration, the swing of the piston rod is regulated, so that the radial deformation of the piston rod of a predetermined amount or more is regulated, and thus, the deformation of the holder member and the seal member can be prevented.

In the power cylinder according to the ninth aspect, as described above, a thin portion having an inner diameter larger than that of the other portion is formed at the opening edge portion of the cylinder tube, so that an annular shape is formed inside the cylinder tube. A step portion is formed, and the outward flange portion of the holder member is locked to the annular step portion, and the thin portion is bent inward along the outer surface of the outward flange portion to form the bent thin portion and the annular portion. Since the outward flange portion is sandwiched and fixed between the stepped portion and the stepped portion, the holder member can be assembled in the cylinder tube with a simple structure while being surely positioned and fixed in the axial direction.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In the embodiment of the present invention, a case where the power steering device is used as a power cylinder of a power steering device for assisting the steering force of the vehicle will be described. Figure 1
FIG. 1 is a cross-sectional view showing a main part of a power cylinder according to an embodiment of the present invention, in which 1 is a cylinder tube, 2 is a piston rod, 3 is a holder member, 4 is a bush, 5 is a seal member, and 6 is a seal member. Is a stopper member, and 7 is a boot cover.

The holder member 3 is formed by press-molding a single metal plate material. That is, the holder member 3, as shown in detail in FIGS.
An outer cylinder portion 31 that is press-fitted and retained in the inner peripheral portion of the cylinder tube 1, and an inner cylinder portion 32 that retains the bush 4 in the inner peripheral portion.
A folded connection portion 33 provided in a state of connecting the inner tubular portion 32 and the outer tubular portion 31, and an outwardly folded end portion of the outer tubular portion 31 opposite to the connection portion 33. An outward flange portion 34 formed by bending and an inward flange portion 35 formed by bending inward at an opening end portion of the inner tubular portion 32 opposite to the connecting portion 33. Also, the connecting portion 3
A plane portion 33 a orthogonal to the axial direction of the cylinder tube 1 is formed on the surface of the cylinder tube 3 facing the seal member 5.

On the other hand, at the opening edge of the cylinder tube 1, a thin portion 11 having an inner diameter larger than that of the other portion is formed, as shown in an enlarged view of an essential part of FIG. An annular step portion 12 is formed on the inside of the annular step portion 12, and the outward flange portion 34 of the holder member 3 is formed on the annular step portion 12.
Is locked and the thin portion 11 is attached to the outward flange portion 34.
Is bent inward along the outer surface of the outer peripheral surface and is fixed in a state where the outward flange portion 34 is sandwiched between the bent thin portion 11a and the annular step portion 12.

The seal member 5 is a reinforcing ring 5 having an L-shaped cross section.
The seal lip 52 is baked and fixed to the inside of 1,
One piece of the reinforcing ring 51 having the L-shaped cross section is the cylinder tube 1.
While being press-fitted into the inner peripheral portion of the above, the other piece is brought into contact with the flat surface portion 33a of the connecting portion 33 of the holder member 3.

The bush 4 is press-fitted and held on the inner periphery of the inner cylindrical portion 32 of the holder member 3, and
The inward flange portion 35 and the reinforcing ring 51 having an L-shaped cross section are prevented from moving in the axial direction.

The stopper member 6 has a piston rod through hole 61 in the center thereof and is provided with its outer peripheral edge side being locked to the bent thin portion 11a which is the opening end of the cylinder tube 1. The annular stopper portion 62 and the fitting portion 63 extending in the axial direction of the cylinder tube 1 from the outer peripheral edge portion of the stopper portion 62 and fitted to the outer circumference of the opening end portion of the cylinder tube 1 have an L-shaped cross section. It is formed into a shape.
The diameter of the piston rod through hole 61 is set so that the inner peripheral surface thereof is close to the outer peripheral surface of the piston rod 2.

The boot cover 7 has a locking annular projection 71 formed on the inner surface of the opening edge portion thereof, and an annular groove 72 is formed on the outer peripheral surface side of the locking annular projection 71. The locking annular projection 71 is mounted on the outer peripheral surface of the end portion of the cylinder tube 1 in a state of being locked to the end surface of the fitting portion 63 of the stopper member 6, and the annular groove 72 portion on the outer periphery thereof is used as a fastening belt or the like. The fastening to the cylinder tube 1 is performed by fastening with the fastener 73.

Next, the operation and effect of the embodiment of the invention will be described. In the power cylinder of the embodiment of the present invention,
As described above, by pressing one metal plate material, the outer cylinder portion 31, the inner cylinder portion 32, and the folded portion provided in a state where the inner cylinder portion 32 and the outer cylinder portion 31 are connected to each other. The inner cylindrical portion 3 in which the bush 4 is press-fitted and held around the connecting portion 33 as a center is formed by the connecting portion 33.
The second side has a sufficient flexibility. Therefore, when the piston rod 2 receives an input from the outside, such as when the wheel rides on a curb on the road, the impact between the piston rod 2 and the bush 4 is affected by the flexibility of the holder member 3. It is absorbed, and this has the effect of reducing the collision noise.

Further, since the flat portion 33a is formed in the connecting portion 33 with which the seal member 5 is abutted and held, the close contact between the seal member 5 and the flat portion 33 is increased, whereby the seal member 5 is formed. It becomes possible to improve the holding accuracy of the.

Further, since the bush 4 is press-fitted and held in the inner peripheral portion of the inner cylindrical portion 32 of the holder member 3, the bush 4 and the holder member 3 are not formed with the engaging and fixing concave and convex portions. The bush 4 can be held by the holder member 3. Further, the bush 4
Is in a state in which its axial movement is blocked by the inward flange portion 35 formed by bending the inner cylindrical portion 32 of the holder member 3 and the L-shaped reinforcing ring 51 of the seal member 5, whereby the bush 4 is formed. The positioning and fixing can be performed easily and surely.

The outer cylinder portion 3 of the holder member 3
1, the outward flange portion 34 is bent and formed, while the opening edge portion of the cylinder tube 1 is formed with a thin portion 11 having an inner diameter larger than other portions, so that the inside of the cylinder tube 1 is formed. An annular step portion 12 is formed on the outer peripheral surface of the holder member 3. The annular flange portion 12 is engaged with the outward flange portion 34 of the holder member 3, and the thin portion 11 is bent inward along the outer surface of the outward flange portion 34. By adopting a structure in which the outward flange portion 34 is sandwiched between the bent thin portion 11a and the annular step portion 12, the holder member 3 is reliably positioned and fixed in the axial direction with a simple structure. The cylinder tube 1 can be assembled in this state.

Further, an annular stopper portion 62 is provided at the opening end portion of the cylinder tube 1, and an opening end portion of the cylinder tube 1 is extended from the outer peripheral edge portion of the stopper portion 62 in the axial direction of the cylinder tube 1. Fitting portion 6 fitted to the outer circumference
By providing the stopper member 6 composed of 3 and 3, the stopper function of restricting the movement of the tie rod can be exerted with a simple structure, and the fitting portion 63 is fitted to the opening end portion of the cylinder tube 1. By doing so, the rigidity of the cylinder tube 1 and the holder member 3 can be enhanced, and the stepped portion formed by the fitting portion 63 can be used as a locking stepped portion when the boot cover 7 is attached. Therefore, it is not necessary to specially form a locking annular step portion, an annular groove, or the like on the outer circumference of the end portion of the cylinder tube 1, and this can reduce the cost.

The inner diameter of the piston rod through hole 61 is set so that the inner peripheral surface of the piston rod through hole 61 of the stopper portion 62 of the stopper member 6 approaches the outer peripheral surface of the piston rod 2. By restricting the swing of the piston rod 2, the radial deformation of the piston rod 2 of a predetermined amount or more is restricted, and thus, the deformation of the holder member 3 and the seal member 5 can be prevented.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to the embodiments of the present invention, and design changes and the like within a range not departing from the gist of the present invention. Even so, it is included in the present invention. For example, in the embodiment of the invention, the example in which the invention is applied to the power cylinder of the power steering device is shown, but it can be used as a hydraulic actuator in all other devices.

[0036]

As described above, in the power cylinder according to the first aspect of the present invention, since the holder member is formed by press molding of the plate material, the holder member has flexibility. Even when the piston rod is held and an external input is applied to the piston rod in the radial direction, the impact between the piston rod and the bush is absorbed by the flexibility of the holder member, thereby reducing the collision noise. The effect of becoming

According to a second aspect of the power cylinder, in the power cylinder according to the first aspect, the bush is press-fitted and held in the inner peripheral portion of the holder member, so that the bush and the holder member are engaged and fixed. The bush can be held by the holder member without forming irregularities or the like.

According to a third aspect of the present invention, there is provided a power cylinder according to the first or second aspect, wherein the outer peripheral portion of the holder member is formed with a bent outward flange portion that engages with the cylinder tube. As a result, the holder member can be easily positioned and fixed.

The power cylinder according to claim 4 is the power cylinder according to any one of claims 1 to 3.
Since the inward flange portion that prevents the axial movement of the bush is bent is formed on the inner peripheral portion of the holder member, the bush can be easily positioned and fixed.

The power cylinder according to claim 5 is the power cylinder according to any one of claims 1 to 4,
By using the power cylinder as a power cylinder of a power steering device that assists the steering force of the vehicle, the impact between the piston rod and the bush due to road surface input is absorbed by the flexibility of the holder member, As a result, the collision noise can be reduced and the discomfort given to the driver can be reduced.

A power cylinder according to claim 6 is the power cylinder according to any one of claims 1 to 5,
The holder member is provided in a state in which an outer tubular portion held on the inner peripheral portion of the cylinder tube, an inner tubular portion holding the bush, and a connection between the inner tubular portion and the outer tubular portion are connected to each other. The holder member is provided inside the cylinder tube and is configured to include a connecting portion that axially supports the seal member, and a surface of the connecting portion facing the seal member is a plane orthogonal to the axial direction of the cylinder tube. By using the means in which the portion is formed, it is possible to provide the inner cylinder portion side with sufficient flexibility centering on the connection portion, and thereby it is possible to enhance the impact noise reduction effect. Further, the seal member is axially supported by the flat surface portion of the connection portion, whereby the adhesion between the seal member and the flat surface portion is increased, and the holding accuracy of the seal member can be improved.

A power cylinder according to claim 7 is the power cylinder according to any one of claims 1 to 6, wherein
A stopper member for restricting the movement of the tie rod is provided at the opening end portion of the cylinder tube, and the stopper member has the piston rod through hole at the center thereof and the outer peripheral edge side thereof is the opening of the cylinder tube. An annular stopper portion that is provided in a state of being locked to the end portion, and a fitting that extends from the outer peripheral edge portion of the stopper portion in the axial direction of the cylinder tube and is fitted to the outer periphery of the opening end portion of the cylinder tube. The stopper function can be exerted with a simple structure by adopting a means composed of a cylinder part and a fitting part, and by fitting the fitting part to the opening end of the cylinder tube, Since the rigidity can be increased and the step formed by the fitting portion can be used as a step for locking when the boot cover is attached,
It is not necessary to specifically form an engaging annular step portion, an annular groove, or the like on the outer circumference of the end portion of the cylinder tube, which makes it possible to reduce the cost.

The power cylinder according to claim 8 is the power cylinder according to claim 7, wherein the inner peripheral surface of the piston rod through hole of the stopper portion of the stopper member is close to the outer peripheral surface of the piston rod. By setting the inner diameter of the through hole so as to regulate the swing of the piston rod, the radial deformation of the piston rod of a predetermined amount or more is regulated, and as a result, the holder member is formed. Also, the deformation of the seal member can be prevented.

A power cylinder according to claim 9 is the power cylinder according to any one of claims 3 to 8.
An annular step portion is formed inside the cylinder tube by forming a thin portion having an inner diameter larger than that of the other portion at the opening edge portion of the cylinder tube, and the outward flange of the holder member is formed on the annular step portion. The part is locked,
The thin portion is bent inward along the outer surface of the outward flange portion, and the outward flange portion is sandwiched and fixed between the bent thin portion and the annular step portion, thereby providing a simple structure. Thus, it becomes possible to assemble the holder member in the cylinder tube in a state where the holder member is reliably positioned and fixed in the axial direction.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a power cylinder according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a holder member in the power cylinder according to the embodiment of the present invention.

FIG. 3 is a vertical sectional view taken along the line III-III in FIG.

FIG. 4 is a perspective view showing a holder member in the power cylinder according to the embodiment of the present invention.

FIG. 5 is a partially enlarged cross-sectional view showing a main part of the power cylinder according to the embodiment of the present invention.

FIG. 6 is a sectional view showing a conventional power cylinder.

[Explanation of symbols]

1 cylinder tube 2 piston rod 3 Holder member 4 bush 5 Seal member 6 Stopper member 7 boots cover 11 thin section 12 annular step 11a Thin bent portion 31 Outer cylinder 32 Inner tube 33 Connection 33a Flat part 34 Outward flange 35 Inward flange 51 Reinforcement ring with L-shaped cross section 52 seal lip 61 Piston rod through hole 62 Stopper 63 Fitting part 71 Locking projection 72 annular groove 73 Fastener

Continued front page    F-term (reference) 3D033 HA00                 3H081 AA03 BB02 CC01 CC03 CC11                       EE20 EE23 HH08

Claims (9)

[Claims] 1. A cylinder tube, a holder member fitted to an end portion on the inner peripheral side of the cylinder tube, a bush held on the inner peripheral side of the holder member, and slidably held on the bush. A piston rod, a piston provided on the piston rod and defining a hydraulic chamber provided in the cylinder tube, and an axially inner side of the holder member provided between the cylinder tube and the piston rod. A power cylinder having a sealing member for sealing, wherein the holder member is formed by press-molding a plate material. 2. The power cylinder according to claim 1, wherein the bush is press-fitted and held in an inner peripheral portion of the holder member. 3. The power cylinder according to claim 1, wherein an outward flange portion that engages with the cylinder tube is bent and formed on an outer peripheral portion of the holder member. 4. The power cylinder according to claim 1, wherein an inward flange portion that prevents axial movement of the bush is formed in a bent shape on an inner peripheral portion of the holder member. . 5. The power cylinder according to claim 1, wherein the power cylinder is used as a power cylinder of a power steering device that assists a steering force of a vehicle. 6. The holder member connects an outer tubular portion held on the inner peripheral portion of the cylinder tube, an inner tubular portion holding the bush, and the inner tubular portion and the outer tubular portion. And a connecting portion which is provided inside the cylinder tube of the holder member and axially supports the sealing member, and the surface of the connecting portion facing the sealing member is in the axial direction of the cylinder tube. The power cylinder according to any one of claims 1 to 5, characterized in that a flat surface portion orthogonal to is formed. 7. The opening end portion of the cylinder tube includes:
A stopper member for restricting the movement of the tie rod is provided, and the stopper member has the piston rod through hole at the center thereof and is provided in a state in which the outer peripheral edge side thereof is locked to the opening end of the cylinder tube. And a fitting portion that extends in the axial direction of the cylinder tube from the outer peripheral edge portion of the stopper portion and is fitted to the outer circumference of the opening end portion of the cylinder tube. The power cylinder according to any one of claims 1 to 6. 8. The swing of the piston rod is set by setting the inner diameter of the piston rod through hole so that the inner peripheral surface of the piston rod through hole of the stopper portion of the stopper member approaches the outer peripheral surface of the piston rod. The power cylinder according to claim 7, wherein the power cylinder is configured to regulate 9. An annular stepped portion is formed inside the cylinder tube by forming a thin portion having an inner diameter larger than other portions at an opening edge portion of the cylinder tube,
The outward flange portion of the holder member is locked to the annular step portion, and the thin portion is bent inward along the outer surface of the outward flange portion, and the bent thin portion is provided between the bent thin portion and the annular step portion. The power cylinder according to claim 3, wherein the outward flange portion is clamped and fixed.