Shock absorber
A shock absorber includes a damping passage that connects an expanding-side chamber with a contracting-side chamber inside a cylinder, a housing that forms a pressurizing chamber, a free piston that partitions the pressurizing chamber into an expanding-side pressurizing chamber and a contracting-side pressurizing chamber, an expanding-side passage that connects the expanding-side chamber with the expanding-side pressurizing chamber, a contracting-side passage that connects the contracting-side chamber with the contracting-side pressurizing chamber, a spring element configured to suppress displacement of the free piston, a cushion configured to collide with the free piston to suppress displacement of the free piston thereover when the free piston is displaced from the neutral position with respect to the housing by a predetermined displacement amount or more; and a cushion fixing member fixed to the housing, the cushion fixing member holding the cushion.
1. A shock absorber comprising:
a cylinder;
a piston slidably inserted into the cylinder, the piston partitioning the cylinder into an expanding-side chamber and a contracting-side chamber;
a piston rod having one end connected to the piston;
a damping passage that connects the expanding-side chamber with the contracting-side chamber;
a housing that forms a pressurizing chamber;
a free piston slidably inserted into the pressurizing chamber, the free piston partitioning the pressurizing chamber into an expanding-side pressurizing chamber and a contracting-side pressurizing chamber;
an expanding-side passage that connects the expanding-side chamber with the expanding-side pressurizing chamber;
a contracting-side passage that connects the contracting-side chamber with the contracting-side pressurizing chamber;
a spring element configured to position the free piston in a neutral position with respect to the housing, the spring element exerting a biasing force for suppressing displacement of the free piston from the neutral position;
a cushion configured to collide with the free piston to suppress displacement of the free piston thereover when the free piston is displaced from the neutral position with respect to the housing by a predetermined displacement amount or more; and
a cushion fixing member fixed to the housing, the cushion fixing member holding the cushion, wherein
the housing has:
a nut portion having a brim in an outer circumference, the nut portion fixing the piston to the piston rod, and
a bottomed cylindrical housing cylinder having a tubular portion hanging down from the brim and a bottom portion closing an end of the tubular portion,
the tubular portion has:
a large inner-diameter portion in a nut portion side, the large inner-diameter portion making sliding contact with the free piston,
a small inner-diameter portion opposite to the nut portion, and
a step portion formed between the large inner-diameter portion and the small inner-diameter portion,
the cushion has an annular shape, the cushion being stacked on the step portion, and
the cushion fixing member has:
a tubular press fitting portion forcibly inserted into the tubular portion, and
a fixing portion extending from the press fitting portion, the fixing portion fixing the cushion to the housing.
2. The shock absorber according to claim 1 , wherein
the press fitting portion is forcibly inserted into the small inner-diameter portion, and
the fixing portion is fitted to an inner circumference of the cushion, the fixing portion fixing the cushion to the housing.
3. The shock absorber according to claim 1 , wherein
the press fitting portion is forcibly inserted into the large inner-diameter portion, and
the fixing portion is fitted to the outer circumference of the cushion, the fixing portion fixing the cushion to the housing.
4. The shock absorber according to claim 1 , wherein
the press fitting portion is forcibly inserted into the small inner-diameter portion,
the fixing portion is a flange, the fixing portion protruding from one end of the press fitting portion to an outer circumference side, the fixing portion being stacked on the step portion, and
the cushion has an annular shape, the cushion being fixed to the housing through welding or fusing to the fixing portion.
5. A shock absorber comprising:
a cylinder;
a piston slidably inserted into the cylinder, the piston partitioning the cylinder into an expanding-side chamber and a contracting-side chamber;
a piston rod having one end connected to the piston;
a damping passage that connects the expanding-side chamber with the contracting-side chamber;
a housing that forms a pressurizing chamber;
a free piston slidably inserted into the pressurizing chamber, the free piston partitioning the pressurizing chamber into an expanding-side pressurizing chamber and a contracting-side pressurizing chamber;
an expanding-side passage that connects the expanding-side chamber with the expanding-side pressurizing chamber;
a contracting-side passage that connects the contracting-side chamber with the contracting-side pressurizing chamber;
a spring element configured to position the free piston in a neutral position with respect to the housing, the spring element exerting a biasing force for suppressing displacement of the free piston from the neutral position;
a cushion configured to collide with the free piston to suppress displacement of the free piston thereover when the free piston is displaced from the neutral position with respect to the housing by a predetermined displacement amount or more; and
a cushion fixing member fixed to the housing, the cushion fixing member holding the cushion, wherein
the housing has:
a nut portion having a brim in an outer circumference, the nut portion fixing the piston to the piston rod, and
a bottomed cylindrical housing cylinder having a tubular portion hanging down from the brim and a bottom portion closing an end of the tubular portion,
the cushion has an annular shape, the cushion being stacked on the brim, and
the cushion fixing member has an annular fixing portion gripped by the tubular portion, the annular fixing portion being fitted to the outer circumference of the cushion, the annular fixing portion fixing the cushion to the housing.
6. A shock absorber comprising:
a cylinder;
a piston slidably inserted into the cylinder, the piston partitioning the cylinder into an expanding-side chamber and a contracting-side chamber;
a piston rod having one end connected to the piston;
a damping passage that connects the expanding-side chamber with the contracting-side chamber;
a housing that forms a pressurizing chamber;
a free piston slidably inserted into the pressurizing chamber, the free piston partitioning the pressurizing chamber into an expanding-side pressurizing chamber and a contracting-side pressurizing chamber;
an expanding-side passage that connects the expanding-side chamber with the expanding-side pressurizing chamber;
a contracting-side passage that connects the contracting-side chamber with the contracting-side pressurizing chamber;
a spring element configured to position the free piston in a neutral position with respect to the housing, the spring element exerting a biasing force for suppressing displacement of the free piston from the neutral position;
a cushion configured to collide with the free piston to suppress displacement of the free piston thereover when the free piston is displaced from the neutral position with respect to the housing by a predetermined displacement amount or more; and
a cushion fixing member fixed to the housing, the cushion fixing member holding the cushion, wherein
the housing has:
a nut portion having a brim in an outer circumference, the nut portion fixing the piston to the piston rod, and
a bottomed cylindrical housing cylinder having a tubular portion hanging down from the brim and a bottom portion closing an end of the tubular portion,
the spring element has:
an expanding-side spring housed in the expanding-side pressurizing chamber, the expanding-side spring being interposed between the free piston and the brim and
a contracting-side spring housed in the contracting-side pressurizing chamber, the contracting-side spring being interposed between the free piston and the bottom portion,
the cushion has an annular shape, the cushion being stacked on the brim, and
the cushion fixing member has:
an annular seat portion interposed between the brim and the expanding-side spring, and
a fixing portion erected from an outer circumference of the seat portion, the fixing portion being fitted to an inner circumference of the cushion, the fixing portion fixing the cushion to the housing.
7. The shock absorber according to claim 5 , wherein the tubular portion has:
a large inner-diameter portion in a nut portion side, the large inner-diameter portion making sliding contact with the free piston,
a small inner-diameter portion opposite to the nut portion, and
a step portion formed between the large inner-diameter portion and the small inner-diameter portion.
8. The shock absorber according to claim 6 , wherein the tubular portion has:
a large inner-diameter portion in a nut portion side, the large inner-diameter portion making sliding contact with the free piston,
a small inner-diameter portion opposite to the nut portion, and
a step portion formed between the large inner-diameter portion and the small inner-diameter portion.
9. A shock absorber comprising:
a cylinder;
a piston slidably inserted into the cylinder, the piston partitioning the cylinder into an expanding-side chamber and a contracting-side chamber;
a piston rod having one end connected to the piston;
a damping passage that connects the expanding-side chamber with the contracting-side chamber;
a housing that forms a pressurizing chamber;
a free piston slidably inserted into the pressurizing chamber, the free piston partitioning the pressurizing chamber into an expanding-side pressurizing chamber and a contracting-side pressurizing chamber;
an expanding-side passage that connects the expanding-side chamber with the expanding-side pressurizing chamber;
a contracting-side passage that connects the contracting-side chamber with the contracting-side pressurizing chamber;
a spring element configured to position the free piston in a neutral position with respect to the housing, the spring element exerting a biasing force for suppressing displacement of the free piston from the neutral position;
a cushion configured to collide with the free piston to suppress displacement of the free piston thereover when the free piston is displaced from the neutral position with respect to the housing by a predetermined displacement amount or more; and
a cushion fixing member fixed to the housing, the cushion fixing member holding the cushion, wherein
the housing has:
a nut portion having a brim in an outer circumference, the nut portion fixing the piston to the piston rod, and
a bottomed cylindrical housing cylinder having a tubular portion hanging down from the brim and a bottom portion closing an end of the tubular portion,
the tubular portion has:
a large inner-diameter portion in a nut portion side, the large inner-diameter portion making sliding contact with the free piston,
a small inner-diameter portion opposite to the nut portion, and
a step portion formed between the large inner-diameter portion and the small inner-diameter portion,
the cushion has an annular shape, the cushion being stacked on the step portion, and
the cushion fixing member has:
a tubular threaded portion screwed to an inner circumference of the small inner-diameter portion, and
a fixing portion extended from the tubular threaded portion, the fixing portion fixing the cushion to the housing.