Cylinder device

1. A cylinder device comprising:

a housing;

a slidable shaft which is slidably movably disposed inside the housing and projectable out of the housing;

a joint member connected to the end section of the slidable shaft; and

a stopper member disposed at a joint section between the slidable shaft and the joint member so as to be brought into contact with an end section of the housing to stop a relative slidable movement between the slidable shaft and the housing and to provide a buffering function during contact of the slidable shaft to the housing;

wherein

the end section of the slidable shaft is partially cutout to form an axial engagement surface exposed at a tip end of the slidable shaft including an end face whose surface area is smaller than a cross-sectional area of the end section;

the slidable shaft and the joint member are connected to each other in a condition where the end face of the slidable shaft is in contact with an end face of the joint member so that a groove is formed between the axial engagement surface of the slidable shaft and the end face of the joint member; and

the stopper member is formed annular to have an opening so as to be mountable on an outer peripheral surface of the slidable shaft and has an engagement section formed along an inner periphery of the stopper member, the engagement section of the stopper member being fitted in the groove so that the stopper member is prevented from at least an axial movement.

2. A cylinder device as claimed in claim 1 , wherein the stopper member is formed of only an elastomeric material and in contact with the end face of the joint member so as to be supported by the joint member.

3. A cylinder device as claimed in claim 1 , wherein an axial distance of the axial engagement surface from the end face of the end section of the slidable shaft is substantially equal to a thickness of a main body section of the stopper, wherein the engagement section of the stopper member is generally annular and has a thickness substantially equal to the thickness of the main body section, the annular engagement section radially inwardly protruding from the main body section.

4. A cylinder device as claimed in claim 1 , wherein 1 , wherein an outer peripheral portion of the end section of the slidable shaft is obliquely cutout to form an annular tapered surface, wherein the engagement section of the stopper member is generally annular and formed along its inner periphery with a tapered surface in contact with the tapered surface of the end section of the slidable shaft.

5. A cylinder device as claimed in claim 1 , wherein the engagement section of the stopper member is generally annular and has first two parallel flat surfaces located at an inner periphery of the annular engagement section, and second two parallel flat surfaces located at an inner peripheral surface which is adjacent to the annular engagement section and in contact with the outer peripheral surface of the slidable shaft.

6. A cylinder device as claimed in claim 1 , wherein the cylinder device is a power cylinder of a power steering system.

7. A method of assembling a cylinder device including a housing, a slidable shaft which is slidably movably disposed inside the housing and projectable out of the housing, a joint member connected to the end section of the slidable shaft, and a stopper member disposed at a joint section between the slidable shaft and the joint member so as to be brought into contact with an end section of the housing to stop a relative slidable movement between the slidable shaft and the housing and to provide a buffering function during contact of the slidable shaft to the housing, the assembling method comprising the following steps of:

providing the slidable shaft whose end section is partially cutout to form an axial engagement surface exposed at a tip end of the slidable shaft including an end face whose surface area is smaller than a cross-sectional area of the end section;

providing the stopper member formed annular to have an opening so as to be mountable on an outer peripheral surface of the slidable shaft and having an engagement section formed along an inner periphery of the stopper member; and

connecting the slidable shaft and the joint member to each other in a condition where the end face of the slidable shaft is in contact with an end face of the joint member so that a groove is formed between the axial engagement surface of the slidable shaft and the end face of the joint member, and the engagement section of the stopper member is fitted in the groove so that the stopper member is prevented from at least an axial movement.

8. A method as claimed in claim 7 , wherein stopper member providing step includes forming the stopper member of only an elastomeric material to be in contact with the end face of the joint member so as to be supported by the joint member.

9. A method as claimed in claim 7 , wherein the stopper member providing step includes forming the stopper member such that a thickness of a main body section of the stopper is substantially equal to an axial distance of the axial engagement surface from the end face of the end section of the slidable shaft, and such that the engagement section of the stopper member is generally annular and has a thickness substantially equal to the thickness of the main body section, the annular engagement section radially inwardly protruding from the main body section.

10. A method as claimed in claim 7 , wherein the slidable shaft providing step includes obliquely cutting out an outer peripheral portion of the end section of the slidable shaft to form an annular tapered surface, wherein the stopper member providing step includes forming the stopper member such that the engagement section of the stopper member is generally annular and formed along its inner periphery with a tapered surface in contact with the tapered surface of the end section of the slidable shaft.

11. A method as claimed in claim 7 , wherein the stopper member providing step includes forming the stopper member such that the engagement section of the stopper member is generally annular and has first two parallel flat surfaces located at an inner periphery of the annular engagement section, and second two parallel flat surfaces located at an inner peripheral surface which is adjacent to the annular engagement section and in contact with the outer peripheral surface of the slidable shaft.

12. A method as claimed in claim 7 , wherein the cylinder device is a power cylinder of a power steering system.