JPH09323660A - Power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leakage of pressure fluid without increase in production cost by adopting a light weight type of a pressure receiving portion for generation of a steering boost force with a dual structure made of synthetic resin and metal and strongly fixing of piping connected with a port of a hydraulic fluid. SOLUTION: A hydraulic actuator for generating the steering boost force and at least one of the pressure receiving portions of a housing of a hydraulic control valve comprise: outside portions 6a, 19a made of a synthetic resin; and inside portions made of a metal 6b, 19b. Metal cylindrical pipe couplers 52, 78 are fixed inside cylindrical synthetic resin protrusions 51, 77 extending outerward of outside portions 6a, 19a. A ring seal member 85 is pressed-in between the outer periphery of the pipes 71, 72, 73, 74, which are inserted in the couplers 52, 78 and the inner periphery of the protrusions 51, 77 in a space inside the ports 32, 34, 40, 75, 76 for the hydraulic fluid which are formed by the inner holes of the couplers 52, 78 rather than between the couplers 52, 78 and the protrusions 51, 77.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering device for generating a steering assist force by pressure oil.

[0002]

2. Description of the Related Art As a power steering device, a hydraulic cylinder for generating a steering assist force and a control valve for controlling the hydraulic pressure acting on a piston partitioning the cylinder tube of the hydraulic cylinder are controlled by the movement of a valve member in a valve housing. The one provided with is used.

Conventionally, the cylinder tube and the valve housing have been made of metal, which has been a cause of increasing the weight of the vehicle.

[0004]

It is considered that the cylinder tube and the valve housing are made of synthetic resin in order to reduce the weight.

However, since the ambient temperature of the power steering device reaches about 120 ° C., the pressure oil inside the cylinder tube and the valve housing becomes high temperature and high pressure.
Therefore, if the cylinder tube and the valve housing are made of synthetic resin, the amount of thermal deformation increases, the clearance between the piston and the valve member inside exceeds the allowable value, and steering assist cannot be performed properly.

Further, when the cylinder tube and the valve housing are molded from a synthetic resin material, the dimensional accuracy such as the roundness on the inner peripheral side becomes low, so that oil leakage occurs between the piston and the valve member inside. Machining is required after the molding so that it does not occur, which increases the manufacturing cost.

Therefore, it can be considered that the hydraulic pressure receiving portion of the cylinder tube or the valve housing is composed of an outer member made of synthetic resin and an inner member made of metal. As a result, the weight can be reduced as compared with the case of molding only from metal. Further, by making the inner member made of metal to reduce the amount of thermal deformation, it is possible to prevent the clearance between the inner member and the piston or the valve member from exceeding the allowable value. Furthermore, even if the outer member is not machined after being molded from a synthetic resin material, the dimensional accuracy such as the roundness of the inner member does not decrease, and the hydraulic pressure receiving portion and the piston or valve member It is possible to prevent oil leakage between the two.

However, when the outer member of the cylinder tube or the valve housing is made of synthetic resin, it becomes difficult to firmly fix the pipe connected to the hydraulic oil port. That is, in the case of using a flare pipe joint, for example, the pipe is fixed by screwing a male screw on the pipe side and a female screw on the port side. Therefore, if the port side is made of synthetic resin, there is a problem that a sufficient fixed torque cannot be secured.

It is an object of the present invention to provide a power steering device which can solve the above problems.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a hydraulic actuator for generating steering assist force and a hydraulic control valve acting on the hydraulic actuator, and the hydraulic pressure is received in at least one of the actuator housing and the valve housing. The part has an outer member made of synthetic resin and an inner member made of metal, and is provided with a cylindrical synthetic resin projecting portion projecting outward from the outer member, and is made of metal fixed in the projecting portion. A tubular pipe connecting tool is provided, and an inner peripheral hole of the connecting tool is applied to a power steering device that constitutes a hydraulic oil port in at least one of the actuator housing and the valve housing.

A hydraulic pressure receiving portion of at least one of the actuator housing and the valve housing is
By using a synthetic resin material and a metal material, it is possible to reduce the weight as compared with using only a metal. Further, by making the hydraulic pressure receiving portion made of metal to reduce the amount of thermal deformation, it is possible to prevent the clearance between the internal piston and the valve member from exceeding the allowable value. Furthermore, even if the outer member is not machined after being molded from a synthetic resin material, the dimensional accuracy such as the roundness of the inner member does not decrease, and the hydraulic pressure receiving portion and the piston or valve member It is possible to prevent oil leakage between the two. A metal pipe connector is fixed in the protruding portion outward from the outer member, and the inside of the connector is used as a hydraulic oil port, so that the pipe connected to the port is made of metal. Can be firmly fixed to.

In the present invention, an annular seal member is formed by the outer circumference of the pipe inserted into the connecting tool and the inner circumference of the protruding section on the inner side of the port than between the facing portions of the connecting tool and the protruding section. It is characterized by being sandwiched. Thereby, the seal member can prevent the pressure oil from flowing into the gap between the facing portion of the projecting portion and the connecting member.

The inner end side of the connecting tool is inserted into an annular groove formed on the inner peripheral side of the projecting portion, and the fastener is screwed into an internal thread formed on the inner peripheral side of the connecting tool to form the annular shape. It is preferable that the seal member is sandwiched between the inner circumference of the protrusion inside the groove and the outer circumference of the pipe. This allows
At the same time as connecting the pipe to the port, the sealing member can be sandwiched.

Further, the present invention is characterized in that the outer member and the protrusion are integrated after the annular seal member is sandwiched between the protrusion and the inner member. Thus, the seal member can prevent the pressure oil from leaking from the port to the outside through the gap between the outer member and the metal inner member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

A rack and pinion type hydraulic power steering system 1 shown in FIG. 1 has an input shaft 2 connected to a steering wheel (not shown) and a relative rotation of the input shaft 2 via a torsion bar 3 in accordance with steering resistance. And an output shaft 4 which is operably connected. A pinion 7 is formed on the output shaft 4, and a rack 8 meshing with the pinion 7 is connected to a steering wheel (not shown). The input shaft 2 is supported by the valve housing 6 via a bearing 5. The output shaft 4 is supported by the rack housing 11 via a ball bearing 12 and a needle bearing 13. One end of the rack 8 protruding from the rack housing 11 is a cylinder tube (actuator housing).
Covered by 19. The rotation of the steering of the input shaft 2 is transmitted to the pinion 7 via the torsion bar 3, so that the rack 8 moves in the vehicle width direction. The wheels are steered by the movement of the rack 8. An oil seal 1 is provided between the input / output shafts 2 and 4 and the valve housing 6.
4 and 15 are provided. A support yoke 16 that supports the rack 8 is also supported by the rack housing 11.

A hydraulic cylinder 18 is provided as a hydraulic actuator that applies a steering assist force. The hydraulic cylinder 18 includes the cylinder tube 19 and the rack 8
And a piston 20 integrated into the main body. The piston 20 partitions the interior of the cylinder tube 19 to form a pair of oil chambers 21 and 22. One oil chamber 2
An oil seal 45 is arranged between the rack 8 and the cylinder tube 19 at the end of No. 1. The other oil chamber 22
A rack bush 46 is arranged between the rack 8 and the cylinder tube 19 at the end of the. An oil seal 47 is arranged between the rack bush 46 and the rack 8, and an O-ring 48 is arranged between the rack bush and the cylinder tube 19. The rack bush 46
Is connected to the cylinder tube 19 by a retaining ring 49.

Oil chambers 21 and 22 of the hydraulic cylinder 18
A rotary hydraulic control valve 23 is connected to the. The control valve 23 is the valve housing 6 described above.
And a tubular first valve member 24 and a second valve member 25 that is inserted into the first valve member 24 so as to be rotatable relative thereto. The first valve member 24 is attached to the output shaft 4 so as to be rotatable together. The second valve member 25 is formed integrally with the outer periphery of the input shaft 2.

As shown in FIG. 2, a plurality of recesses along the axial direction are formed in the inner circumference of the first valve member 24 and the outer circumference of the second valve member 25 at equal intervals in the circumferential direction. The first valve member-side recess is composed of four right steering recesses 27 located at equal intervals in the circumferential direction and four left steering recesses 28 located at equal intervals in the circumferential direction. The second valve member side recesses are composed of four pressure oil supply recesses 29 that are located at equal circumferential intervals, and four pressure oil discharge recesses 30 that are located at equal circumferential intervals. The right steering recesses 27 and the left steering recesses 28 are alternately arranged in the circumferential direction, and the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 are alternately arranged in the circumferential direction. Each right steering recess 27
The first flow path 31 formed in the first valve member 24, and the first port 34 formed in the valve housing 6 and the first flow path formed in the cylinder tube 19 as shown in FIG.
Via a pipe 72 connected to the cylinder port 75,
It communicates with one oil chamber 21 of the hydraulic cylinder 18. Each left steering recess 28 is connected to a second flow passage 33 formed in the first valve member 24, a second port 32 formed in the valve housing 6 and a second cylinder port 76 formed in the cylinder tube 19. The fluid is communicated with the other oil chamber 22 of the hydraulic cylinder 18 via the pipe 71. Each pressure oil supply concave portion 29 is formed by the third flow path 3 formed in the first valve member 24.
5 and inlet port 3 formed in valve housing 6
It is connected to the pump 37 through a pipe 73 connected to the pump 6.
Each of the pressure oil discharge recesses 30 includes a first discharge passage 38 formed in the second valve member 25, a passage 47 between the inner and outer circumferences of the input shaft 2 and the torsion bar 3, and a second discharge passage formed in the input shaft 2. (Not shown), and the tank 41 via a pipe 74 connected to the discharge port 40 formed in the valve housing 6.
Lead to. As a result, the pump 37, the tank 41,
The oil chambers 21 and 22 of the hydraulic cylinder 18 communicate with each other through the inter-valve passage 42 between the inner and outer circumferences of the first valve member 24 and the second valve member 25. Between the first valve member side concave portion and the second valve member side concave portion in the inter-valve flow path 42, there are throttle portions A, B, C, D whose opening degree is changed by relative rotation of both valve members 24, 25. The hydraulic pressure acting on the hydraulic cylinder 18 is controlled by the change in the opening degree of the throttle portions A, B, C, D.

As shown in FIG. 1, each of the ports 32, 3 is
4, 36, 40 and below the second port 32 in the figure, the outer periphery of the first valve member 24 and the valve housing 6
A seal ring 39 is arranged between the inner circumference and the inner circumference of the seal ring 39.

FIG. 2 shows the relative positions of the valve members 24 and 25 at the midpoint of the steering angle where steering is not performed.
In this state, the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 communicate with each other through all the throttles A, B, C, D, so that the pressure oil supplied from the pump 37 is directly supplied to the tank 41.
And the steering assist force is not generated. When the steering wheel is steered to the right from the midpoint, the torsion bar 3 is twisted according to the steering torque, and the valve members 24 and 25 rotate relative to each other. As a result, the opening degree of the throttle portion A between each right steering recess portion 27 and each pressure oil supply recess portion 29 and the throttle portion B between each left steering recess portion 28 and each pressure oil discharge recess portion 30 are reduced. The opening degree becomes large, and the opening degree of the throttle portion C between each left steering recess portion 28 and each pressure oil supply recess portion 29 and the throttle portion between each right steering recess portion 27 and each pressure oil discharge recess portion 30. The opening degree of the portion D becomes smaller. As a result, one oil chamber 21 of the hydraulic cylinder 18 is moved from the pump 37
The pressure oil is supplied to the piston 20, and the hydraulic pressure acts on the piston 20, the pressure oil flows back from the other oil chamber 22 of the hydraulic cylinder 18 to the tank 41, and the steering assist force to the right of the vehicle acts on the rack 8. When the steering wheel is steered to the left from the midpoint of the steering angle, each throttle A,
Since the opening degrees of B, C, and D change in the opposite direction to the case of steering to the right, the steering assist force to the left of the vehicle acts on the rack 8.

The valve housing 6, the rack housing 11, and the cylinder tube 19 are individually molded and then connected.

As shown in FIG. 3, the valve housing 6 has a tubular outer member 6a and a tubular inner member 6b inserted into the outer member 6a. Its outer member 6
a is injection-molded from a synthetic resin material, and its inner member 6
b is formed of a metal material such as steel. During the injection molding of the outer member 6a, the inner member 6b is placed in the molding die.
Is inserted. Examples of the synthetic resin used as the material of the outer member 6a include polyphenylene sulfide (PP).
It is possible to use S) in which 40% by weight of glass fiber is added. An adhesive may be interposed between the outer member 6a and the inner member 6b. By inserting the first valve member 24 into the inner member 6b, the hydraulic pressure receiving portion of the valve housing 6 has a double structure of the outer member 6a and the inner member 6b. The bearing 5 is press-fitted into the inner member 6b and the oil seal 1
4, 15 are inserted.

Each of the hydraulic oil ports 32, 34, 36, 40 in the valve housing 6 has a cylindrical synthetic resin projection 51 which projects outward from the outer member 6a.
An inner peripheral hole of the metal tubular pipe connector 52 fixed inside,
It is constituted by a through hole penetrating the outer member 6a and the inner member 6b. The connector 52 is fixed to the protrusion 51 by being inserted into the molding die when the protrusion 51 is molded. In addition, it is preferable to knurl the outer periphery of the connector 52.

Further, a flange 6d for connection with the rack housing 11 is formed on the outer member 6a, and a metallic cylindrical bolt receiver 53 is inserted into a through hole formed in the flange 6d. The flange 6d and the bolt receiver 53 are, for example, press-fitted into the through hole of the flange 6d while applying ultrasonic vibration to the bolt receiver 53, or the flange 6d.
They are integrated by being inserted into the mold during the molding of d.

As shown in FIGS. 4 and 5, the rack housing 11 is injection-molded with a synthetic resin material, and the insertion hole 11a of the output shaft 4 and the insertion hole 11 of the support yoke 16 are formed.
It has b and the insertion hole 11c of the rack 8.

A cylindrical metal support 56 having a bottom is inserted into one end of the insertion hole 11a of the output shaft 4. The support 56 and the rack housing 11 are, for example, the support 5
6 is press-fitted into the insertion hole 11a while applying ultrasonic vibration, or is inserted into the molding die during molding of the rack housing 11 to be integrated. The ball bearing 12 that supports the output shaft 4 is inserted into the insertion hole 11a, and the needle bearing 13 that supports the output shaft 4 is press-fitted into the support 56. A flange 11d for connection with the valve housing 6 is formed on the outer periphery of the other end of the insertion hole 11a of the output shaft 4, and a metallic cylindrical bolt receiver 54 is inserted into a through hole formed in the flange 11d. There is. The flange 11d and the bolt receiver 54 are integrated by, for example, press-fitting the bolt receiver 54 into a through hole of the flange 11d while applying ultrasonic vibration or inserting the bolt receiver 54 into a molding die when molding the flange 11d. It The bolt receiver 5
4 and the bolt receiver 53 of the valve housing 6 are screwed with the headed bolt, the nut is screwed together,
The valve housing 6 and the rack housing 11 are connected.

Insertion hole 11b of the support yoke 16
A tubular metal guide 57 is inserted in the. The guide 57 and the rack housing 11 are integrated, for example, by press-fitting the guide 57 into the insertion hole 11b while applying ultrasonic vibration, or by inserting the guide 57 into the molding die when molding the rack housing 11. The support yoke 16 is inserted into the guide 57 and pressed against the back surface of the rack 8 by a spring (not shown).

A step 11e is formed on the inner circumference of one end of the insertion hole 11c of the rack 8, and a ball joint (not shown) connected to one end of the rack 8 hits the step 11e, so that one of the left and right sides of the rack 8 is reached. Is restricted to travel.
A flange 11f for connection with the cylinder tube 19 is formed on the outer circumference of the other end of the insertion hole 11c of the rack 8.

As shown in FIG. 6, the cylinder tube 19 includes a cylindrical outer member 19a and the outer member 19a.
And a tubular inner member 19b inserted into the. The outer member 19a is injection molded from a synthetic resin material, and the inner member 19b is molded from a metal material such as steel. When the outer member 19a is injection-molded, the inner member 19b is inserted into the molding die. As the synthetic resin used as the material of the outer member 19a, for example, polyphenylene sulfide (PPS) containing 40% by weight of glass fiber can be used. An adhesive may be interposed between the outer member 19a and the inner member 19b. By inserting the piston 20 into the inner member 19b, the hydraulic pressure receiving portion of the cylinder tube 19 is
It has a double structure of an outer member 19a and an inner member 19b.
The oil seals 45, 47, the rack bushing 46, and the O-ring 48 are arranged between the inner member 19b and the rack 8, and the groove 61 in which the retaining ring 49 is fitted on the inner circumference of the inner member 19b. Are formed. One end of the inner member 19b is an inward flange 19e for receiving the oil seal 45. The outer member 19
The other end of the rack housing 11 is inserted into one end of a, and the inner peripheral surface and the end surface of the outer member 19a on the one end side and the outer peripheral surface of the other end of the rack housing 11 and the flange 1 are inserted.
By being welded to the end surface of 1f, the rack housing 1
1 and the cylinder tube 19 are connected.

Each of the hydraulic oil ports 75 and 76 in the cylinder tube 19 is fixed in a cylindrical synthetic resin projection 77 that projects outward from the outer member 19a. The inner peripheral hole 78 and a through hole penetrating the outer member 19a and the inner member 19b. The connector 78 is fixed to the protrusion 77 by being inserted into the molding die when the protrusion 77 is molded.
In addition, it is preferable to knurl the outer periphery of the connector 78.

As shown in FIG. 7, in the valve housing 6 and the cylinder tube 19, the inner ends of the connecting members 52, 78 which form the respective ports 32, 34, 36, 40, 75, 76 of the hydraulic oil are arranged at their inner ends. The protrusions 51 and 77 are inserted into the annular groove 90 formed on the inner peripheral side. In addition, an annular convex portion 9 that protrudes inward is provided on the inner end portion of each of the connecting members 52 and 78.
1a is formed, and is fitted into a recess 90a formed on the inner circumference of the annular groove 90.

Each port 32, 34, 36, 40, 75,
76 and the pipes 71, 72, 73, 74 are connected by a flare pipe joint. That is, the female screw 80 is formed on the inner circumference of each of the connecting members 52, 78. In addition, each protrusion 51, 7
A taper surface 81 is formed inside the annular groove on the inner periphery of 7 as the diameter decreases toward the inside. Each pipe 71, 7
A tubular metal fastener 83 having a male screw 82 formed on the outer periphery thereof is fitted to 2, 73, and 74. Each pipe 7
Flange 84 is formed on the outer periphery of the end portions of 1, 72, 73, and 74. By screwing the tightening tool 83 into the coupling tools 52, 78, the ports 32, 34, 36, 40, 75, rather than between the facing portions of the coupling tools 52, 78 and the protrusions 51, 77, respectively.
On the inner side of 76, the tapered surface 81 and the flange 8
The first O-ring (annular seal member) 85 is sandwiched between the two. This allows each port 32, 34, 3
6, 40, 75, 76 and the pipes 71, 72, 73, 74 are connected. The protrusions 51 and 77 are formed by molding.

The protrusions 51 and 77 and the outer members 6
a and 19a are the protrusions 51 and 77 and the inner members 6
2nd O-ring (annular seal member) by b and 19b
After 95 is sandwiched, they are integrated. That is, the ports 32, 34, 36, 4 are attached to the outer members 6a, 19a.
The annular protrusions 6a ′, 19 surrounding 0, 75, 76
a 'is formed. A first step 51 is formed on the outer circumference of each of the protrusions 51 and 77 and is in contact with the end faces of the protrusions 6a 'and 19a'.
a and 77a, and the second steps 51b and 77b that contact the second O-ring 95 are formed.

As shown in FIG. 8, the protrusions 51 and 77 and the inner members 6b and 19b, which are molded as separate members, are integrated. That is, the respective protrusions 51, 77 are inserted into the annular protrusions 6a ', 19a', and the second O-rings 95 thereof are provided on the outer peripheral surfaces of the inner members 6b, 19b and the protrusions 5.
After being sandwiched between the first step 77 and the second step 51b, 77b, the end surfaces of the annular projections 6a ', 19a' and the first step 51a, 77a are welded to each other, so that each outer member 6 is welded.
a and 19a and the protrusions 51 and 77 are integrated.

According to the above structure, since the hydraulic pressure receiving portions of the valve housing 6 and the cylinder tube 19 are formed of the synthetic resin material and the metal material, the weight can be reduced as compared with the case of using only the metal. Since the inner peripheral side of the hydraulic pressure receiving portion is made of metal, the amount of thermal deformation is small, and it is possible to prevent the clearance between the internal first valve member 24 and the piston 20 from exceeding an allowable value. Also,
Even if the outer peripheral side of the hydraulic pressure receiving portion is not machined after being molded from a synthetic resin material, the dimensional accuracy such as the roundness on the inner peripheral side does not decrease, and the inner peripheral surface of the hydraulic pressure receiving portion does not decrease. No oil leakage occurs between the first valve member 24 and the piston 20 inside. In addition, each inner member 6b,
19b is in contact with oil on the inner peripheral side and covered with synthetic resin on the outer peripheral side, so that it is not necessary to perform rust-preventive coating, and the cost can be reduced.

Further, the metal connector 5 is provided in the synthetic resin projecting portions 51, 77 projecting outward from the outer members 6a, 19a of the valve housing 6 and the cylinder tube 19, respectively.
By fixing 2, 78, the hydraulic oil ports 32, 34, 36, 40, 75, 7 inside the connecting members 52, 78 are fixed.
The pipes 71, 72, 73, 74 connected to the 6 can be firmly fixed to the connectors 52, 78 made of metal. Since the fixing can be performed by the conventional fixing mechanism using a flare pipe joint or the like, the degree of freedom in design is not limited.

Moreover, the protrusions 51 and 77 and the connecting member 5
The ports 32, 34, 36,
The first O-ring 85 can prevent the pressure oil from flowing in from 40, 75, and 76. The first O-ring 85
Screw the fasteners 83 into the connectors 52, 78 to connect the pipes 71, 72, 73, 74 to the ports 32, 3
4, 36, 40, 75, 76 can be simultaneously pinched.

Further, each protrusion 51, 77 and the inner member 6
a second O-ring 95 between the outer member 6 and the port 32, 34, 36, 40, 75, 76.
It is possible to prevent the pressure oil from leaking to the outside through the gap between the a, 19a and the inner members 6b, 19b.

FIG. 9 shows a comparative example. The difference from the above embodiment is that the first O-ring 85 is connected to the pipes 71, 72, 73, 7
It is sandwiched by the outer periphery of 4 and the inner periphery of the connecting members 52, 78,
The point is that the second O-ring 95 is not arranged. In this case, the pressure oil may leak to the outside through the gaps between the protrusions 51, 77 and the connecting members 52, 78 and the gaps between the outer members 6a, 19a and the inner members 6b, 19b. On the other hand, according to the above-mentioned embodiment, since the pressure oil does not reach between the protrusions 51, 77 and the connecting members 52, 78,
There is no leakage of pressure oil, and the protrusions 51, 7
Since it is not necessary to separately provide a sealing means between the connection member 7 and the connecting members 52, 78, it is possible to prevent an increase in cost. Further, since the second O-ring 95 blocks the flow of the pressure oil reaching between the protrusions 51, 77 and the inner members 6b, 19b, it is possible to prevent the pressure oil from leaking to the outside.

The present invention is not limited to the above embodiment. For example, although the present invention is applied to the rack and pinion type power steering device in the above-described embodiment, it can be applied to, for example, a ball screw type power steering device.

[0042]

According to the power steering apparatus of the present invention, the hydraulic pressure receiving portion for generating the steering assist force can be lightened by using a double structure of a synthetic resin material and a metal material, and can be used as a hydraulic oil port. It is possible to firmly fix the connected pipe, prevent leakage of pressure oil and appropriately maintain the steering assist function without increasing the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power steering device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view of a valve housing according to an embodiment of the present invention.

FIG. 4 is a sectional view of the rack housing according to the embodiment of the present invention.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a sectional view of a cylinder tube according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of an essential part of an embodiment of the present invention.

FIG. 8 is an explanatory diagram of an assembling procedure of main parts of the embodiment of the present invention.

FIG. 9 is a sectional view of a comparative example.

[Explanation of symbols]

 1 Power Steering Device 6 Valve Housing 6a Outer Member 6b Inner Member 18 Hydraulic Cylinder (Hydraulic Actuator) 19 Cylinder Tube (Actuator Housing) 19a Outer Member 19b Inner Member 32, 34, 36, 40, 75, 76 Port 51, 77 Projection Part 52, 78 Connecting tool 71, 72, 73, 74 Piping 83 Tightening tool 85 O-ring 95 O-ring

Claims (4)

[Claims] 1. A power steering apparatus comprising a hydraulic actuator for generating steering assist force and a hydraulic control valve acting on the hydraulic actuator, wherein a hydraulic pressure receiving portion of at least one of the actuator housing and the valve housing is a composite. A tubular connection made of metal, which has a resin-made outer member and a metal-made inner member, is provided with a cylindrical synthetic resin projecting portion projecting outward from the outer member, and is fixed in the projecting portion. Is provided, and the inner peripheral hole of the connecting member constitutes a port for hydraulic oil in at least one of the actuator housing and the valve housing, and is located on the inner side of the port than between the facing portion of the connecting member and the protruding portion. The power that the annular seal member is sandwiched by the outer circumference of the pipe inserted into the connecting tool and the inner circumference of the protruding portion. -Steering device. 2. The inner end side of the connecting tool is inserted into an annular groove formed on the inner peripheral side of the projecting portion, and the tightening tool is screwed into a female screw formed on the inner peripheral side of the connecting tool, The power steering device according to claim 1, wherein the seal member is sandwiched between the inner circumference of the protrusion inside the annular groove and the outer circumference of the pipe. 3. The power steering device according to claim 1, wherein the outer member and the protrusion are integrated after the annular seal member is sandwiched between the protrusion and the inner member. 4. A power steering apparatus comprising a hydraulic actuator for generating steering assist force and a hydraulic control valve acting on the hydraulic actuator, wherein a hydraulic pressure receiving portion of at least one of the actuator housing and the valve housing is a composite. A tubular connection made of metal, which has a resin-made outer member and a metal-made inner member, is provided with a cylindrical synthetic resin projecting portion projecting outward from the outer member, and is fixed in the projecting portion. Is provided, the inner peripheral hole of the connecting tool constitutes a port for hydraulic oil in at least one of the actuator housing and the valve housing, and the outer member and the protruding portion are annular by the protruding portion and the inner member. The power steering device that is integrated after the seal member is sandwiched.