JP2001153103A - Relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and lighten a relief valve and also improve workability at the time of disassembly and assembly by shortening an overall length in a cartridge type relief valve. SOLUTION: A relief valve 9A is composed of a valve tube 33, a valve seat tube 35, a valve element 36, and a lid body 39, etc., as a cartridge type, to fittedly engage the base end side of the tube 33 into the fittedly engaged hole 39F of the body 39, and also the tube 35 and element 36 are preassembled on the tip side of the tube 33. The body 39 is composed of a barrel part 39B having a male screw 39A on the outer peripheral side, a nearly disklike head part 39D positioned on the upper end side of the part 39B and formed into a large diameter than that of the part 39B, and the outer peripheral side is adopted as an annular collar part 39C engagedly mounted on a seat surface 32, and an engaged recess 39E composed of a bottomed hexagon socket formed on the center part side of the part 39D, and the like, as a short size collar- attached plug.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve suitable for use in a traveling hydraulic motor provided in a construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art In general, construction machines such as hydraulic excavators and hydraulic cranes are known as overload relief valves in order to suppress the generation of excessive pressure in a hydraulic circuit when a traveling hydraulic motor or the like is stopped. A relief valve is provided (for example, Japanese Patent Publication No. Hei 7-122441).

[0003] A conventional relief valve of this type has, for example, a casing that forms a part of a motor housing of a hydraulic motor and has a passage through which pressure oil flows, and a casing in which a valve housing hole is formed in the passage. A valve cylinder which is inserted into the valve receiving hole of the casing from the opening end side and has a valve body provided therein, which is provided on a valve seat for relieving excess pressure generated in the passage, and which is detachably seated on the valve seat; In the attached state, the cover is screwed from the outside of the casing to the open end side of the valve accommodating hole, and has a threaded lid for closing the valve accommodating hole.

[0004] Such a relief valve is generally called a cartridge type relief valve, and the valve cylinder accommodating the valve body is preliminarily assembled to a lid, so that the valve cylinder and the valve are opened. The body, the lid, and the like are handled as a single unit, and have advantages such as improved workability during disassembly and assembly.

A portion of the lid protruding from the opening end side of the valve receiving hole to the outside of the casing forms a hexagonal head. When the lid is screwed to the opening end side of the valve receiving hole, A configuration in which a tool such as a wrench is engaged with the hexagonal head, and a rotational torque is applied to the head from the outside of the casing using a tool, whereby the lid is fastened to the opening end side of the valve receiving hole. And

[0006] In the traveling hydraulic circuit provided with such a relief valve, when the traveling vehicle is stopped, the traveling hydraulic motor is rotated by inertia to generate a brake pressure in the passage. I do. When the brake pressure rises to the relief set pressure of the relief valve and becomes an excessive pressure, the valve body of the relief valve is opened by the brake pressure, and the excess pressure at this time is released to the low pressure side.

In this case, the kinetic energy of the brake pressure in the overpressure state is converted into heat energy while passing through the valve seat side of the opened relief valve, whereby the inertia force of the vehicle is gradually absorbed. At the same time, a braking force is applied to the vehicle.

When the vehicle is suddenly stopped, an impact or the like may be generated by opening the relief valve. There is a possibility that the life of the relief valve or the like may be shortened.

Therefore, in the relief valve according to the prior art,
In order to reduce such an impact, a free piston is slidably inserted on the outer peripheral side of the valve cylinder, and an oil storage chamber for temporarily storing pressure oil is formed by the free piston. Is given.

[0010]

In the above-mentioned relief valve of the prior art, the components such as the valve cylinder, valve body and lid are pre-assembled as a single unit. To be configured,
The unit body including the valve body, the valve cylinder, and the lid is easy to handle, and has advantages such as improved workability during disassembly and assembly.

However, the lid is provided with a hexagonal head for applying a rotational torque using a tool such as a wrench, and the head is largely extended from the opening end side of the valve receiving hole to the outside of the casing. Because of the projecting configuration, the components of the relief valve (head of the lid) protrude greatly from the casing, which is the motor housing of the hydraulic motor, which hinders downsizing of the motor housing.

In addition, since the head having a hexagonal outer shape is employed, not only the axial dimension of the lid itself becomes longer, but also the overall length of the relief valve becomes longer, and the relief valve becomes smaller and lighter. There is a problem that can not be converted.

On the other hand, as another prior art, for example, a relief valve described in Japanese Utility Model Laid-Open No. 1-14971 (Japanese Utility Model Publication No. Hei 5-20937) has a cover whose head is formed in a flat disk shape. At the center side, an engagement recess engageable with a tool such as a wrench is provided, thereby reducing the axial dimension of the lid itself.

However, in this case, the valve cylinder (in the publication, the stepped cylinder portion 6) is formed to have a larger diameter than the lid, and the valve body or the like is housed in the valve cylinder while the opening end of the valve cylinder is open. By screwing the lid on the side, these are pre-assembled as a single unit, so it is necessary to form a screw separately from the lid on the outer peripheral side of the valve cylinder, and the relief valve is When finally assembling, it is necessary to screw the male thread into the valve receiving hole of the casing.

[0015] For this reason, a tool is engaged from the outside into the engaging concave portion provided in the head of the lid, and first, when the lid is screwed onto the opening end side of the valve cylinder, a rotational torque is applied. When the male screw of the valve cylinder is screwed into the valve accommodating hole of the casing, it is necessary to apply a rotational torque. An appropriate rotational torque (tightening torque) is applied to the threaded portions of the lid and the valve cylinder. There is a problem that it is difficult to give.

When such a relief valve is detached from the casing and disassembled, there is a possibility that only the lid is detached from the valve cylinder while leaving the valve cylinder in the valve receiving hole of the casing. There is a problem that is bad. There is also a problem that a free piston or the like that gives a shockless function to the relief valve cannot be slidably provided in the valve cylinder.

As another prior art, for example, in a relief valve described in Japanese Patent Application Laid-Open No. Hei 6-137307, a head of a lid is formed in a flat disk shape, and a wrench or the like is provided at the center side thereof. In this case, the valve cylinder itself protrudes from the casing, and the protruding portion is formed in a hexagonal shape. Therefore, there is a problem that the whole cannot be reduced in size and weight.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to reduce the overall length and reduce the size,
An object of the present invention is to provide a relief valve capable of reducing the weight and improving the workability during disassembly and assembly.

[0019]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a casing having a passage through which pressure oil flows and having a valve receiving hole formed in the passage, and a valve of the casing. A valve cylinder having a valve body inserted therein from the opening end side and releasably seated on a valve seat in order to relieve excess pressure generated in the passage; and The present invention is applied to a relief valve including a screwed lid that is screwed from the outside of the casing to the opening end of the valve receiving hole to close the valve receiving hole.

A feature of the structure adopted by the invention of claim 1 is that the cover has a body portion formed with a male screw screwed to an opening end side of the valve accommodating hole on an outer peripheral side. A substantially disk-shaped head which is located on one side in the axial direction of the body portion and has a larger diameter than the body portion and has an annular flange portion whose outer peripheral side is fastened to the seating surface on the casing side; A non-circular engaging recess which is recessed from the end surface of the head toward the body and is engageable with a tool for applying a rotational torque to the male screw; And a fitting portion provided on the side and fitted with and fitted with the valve cylinder.

With such a structure, the valve body is fitted to the fitting portion on the other side in the axial direction on the body of the cover, and the valve body and the valve body are preliminarily assembled to the cover in this state. By inserting this unit body into the valve receiving hole of the casing and screwing the lid on the opening end side, the assembling work of the relief valve can be easily performed. In this case, a rotating torque for tightening can be added to the head of the lid by engaging a tool such as a wrench in the engagement recess, and the protrusion from the bearing surface of the casing is smaller than the disk-shaped head. Can be suppressed.

According to a second aspect of the present invention, an annular seal member is provided on the outer peripheral side of the body of the lid between the flange and the male screw, and the seal member is provided on the opening end side of the valve receiving hole. Is sealed together with the flange. Thereby, the valve housing hole provided in the casing can be sealed to the outside in a liquid-tight manner.

According to the third aspect of the present invention, the fitting portion of the lid is formed at the inside of the male screw in the radial direction and formed in the body portion through the bottomed fitting hole axially opposed to the engaging concave portion. The valve cylinder has a configuration in which one end side is fitted into the fitting hole and preliminarily assembled to the lid. In this case, by fitting the valve cylinder into the fitting hole provided in the body of the lid, the valve body and the valve cylinder can be pre-assembled to the lid to form a unit, and a cartridge type relief can be provided. The valve can be easily assembled to the casing.

According to a fourth aspect of the present invention, the fitting portion of the lid is formed of a fitting projection protruding in the axial direction from the other end surface in the axial direction of the body portion. And is preliminarily assembled to the lid by being fitted to the outer peripheral side. In this case, by fitting the valve cylinder on the outer peripheral side of the fitting projection provided on the body of the lid, the valve body and the valve cylinder can be pre-assembled to the lid to form a unit, The cartridge type relief valve can be easily assembled to the casing.

According to a fifth aspect of the present invention, the axial height H of the head is defined as a unit of millimeter (mm) with respect to the effective diameter D of the male screw and the seating depth T of the casing. , H <(0.3 × D) + T + 5.

Thus, the height H in the axial direction of the head can be reduced, and the dimension (HT) in which the head projects from the casing can be reliably reduced.

According to a sixth aspect of the present invention, the valve cylinder is formed of a stepped cylindrical body having one end fitted to the lid and having a valve element sliding hole at an intermediate position in the longitudinal direction. Has a structure in which a spring chamber for accommodating a valve spring for urging the valve body in the normally closed direction is formed between the valve body and the lid body.

Thus, the valve spring is housed in the spring chamber formed between the lid and the valve in the valve cylinder, and the valve can be normally biased in the valve closing direction, and the valve is opened by the valve spring. The valve pressure (relief set pressure) can be determined.

According to the seventh aspect of the present invention, a valve seat member having a valve seat which is located at the back side of the valve receiving hole and on which the valve element is detachably seated is provided at the other end of the valve cylinder. The valve seat member is preliminarily assembled to the lid via a valve cylinder.

Thus, the valve seat member and the valve body can be pre-assembled to the lid via the valve cylinder, and these can be easily unitized, and the cartridge type relief valve can be easily mounted on the casing. Can be assembled.

Further, according to the invention of claim 8, the casing comprises a motor housing of a traveling hydraulic motor used for a construction machine, and the head of the lid is housed inside the outermost diameter portion of the motor housing. I have. As a result, the head of the lid does not project outward in the radial direction of the motor housing, so that the outer diameter of the motor housing can be reduced, and the traveling hydraulic motor can be reduced in size and weight.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A relief valve according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking an example in which the relief valve is applied to a traveling hydraulic motor of a hydraulic shovel.

FIGS. 1 to 7 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a traveling hydraulic motor provided on a lower traveling body (not shown) of a hydraulic shovel. The hydraulic motor 1 has a motor housing 21 described later as shown in FIGS. In order to drive a shovel (hereinafter referred to as a vehicle), its output shaft is connected to driving wheels 28 via a speed reducer 26 described later.

A hydraulic pump 2 constitutes a hydraulic power source together with a tank 3. The hydraulic pump 2 and the tank 3 are connected to the hydraulic motor 1 through a pair of main lines 4A and 4B as shown in FIG. A direction switching valve 5 is provided in the middle of 4A, 4B. The direction switching valve 5 is switched from the neutral position (a) to the switching positions (b) and (c) by manually tilting the operation lever 5A by the operator,
At these switching positions (b) and (c), the direction of the pressure oil supplied and discharged from the hydraulic pump 2 to the hydraulic motor 1 is switched.

Reference numeral 6 denotes a counterbalance valve which is located between the hydraulic motor 1 and the direction switching valve 5 and is provided in the middle of the main pipelines 4A and 4B. A pair of check valves 7 that allow pressure oil to flow only toward the motor 1 and prevent reverse flow
A and 7B, and a pressure control valve 8 connected in the middle of the main pipelines 4A and 4B so as to be in parallel with the check valves 7A and 7B, and the pressure control valve 8 is connected between the main pipelines 4A and 4B. Is switched from the neutral position (a) to the switching positions (b) and (c) almost in conjunction with the direction switching valve 5 due to the pressure difference.

Here, in the main pipelines 4A and 4B, between the hydraulic pump 2 and the tank 3 and the counter balance valve 6 are hydraulic source side main pipelines 4A1 and 4B1, and between the hydraulic motor 1 and the counter balance valve 6. The motor-side main lines 4A2 and 4B2 are provided. The hydraulic power source side main lines 4A1 and 4B1 and the motor side main lines 4A2 and 4B2 are communicated and shut off by the pressure control valve 8 of the counter balance valve 6 almost in conjunction with the switching operation of the direction switching valve 5. It is.

9A and 9B are located between the hydraulic motor 1 and the counterbalance valve 6 and are located on the motor side main lines 4A2 and 4B.
The relief valves 9A and 9B are constituted by a valve cylinder 33, a valve body 36, a lid body 39 and the like, which will be described later, as shown in FIG. Things. And relief valve 9
When excessive pressure is generated in the motor-side main line 4A2 or 4B2 during the inertial rotation of the hydraulic motor 1, the valves A and 9B open to relieve this pressure to the low-pressure side motor-side main line 4B2 or 4A2.

10A and 10B are accumulators attached to the relief valves 9A and 9B, respectively.
A and 10B are constituted by a free piston 41 described later shown in FIG. And accumulator 1
Reference numerals 0A and 10B provide a shockless function to the relief valves 9A and 9B, and alleviate the shock when the relief valves 9A and 9B are opened.

The relief valves 9A and 9B constitute a brake valve 11 together with the counter balance valve 6 and the like. The brake valve 11 is configured to apply a braking force to the hydraulic motor 1 when the hydraulic motor 1 is rotated by inertia or the like. ing.

Next, referring to FIGS. 2 to 6, the traveling hydraulic motor 1, the relief valve 9A and the accumulator 1 will be described.
The configuration of 0A will be described. Note that the relief valve 9B and the accumulator 10B have substantially the same configuration as the relief valve 9A and the accumulator 10A, and a description thereof will be omitted.

In the drawing, reference numeral 21 denotes a motor housing of the hydraulic motor 1 for traveling. The motor housing 21 has a stepped cylindrical housing body 22 as shown in FIG. An end cover 24 is fixed to the housing body 22 with a plurality of bolts 23, 23,..., And covers one side of the housing body 22. The end cover 24 also serves as a casing of the entire brake valve 11. .

The motor housing 2 of the hydraulic motor 1
1, a large-diameter mounting flange 22A is provided on the other side of the housing body 22, and the mounting flange 22A is formed as a circular plate as shown in FIG. The mounting flange 22A has a plurality of bolt mounting holes 22.
B, 22B,... Are drilled, and the motor housing 21 of the hydraulic motor 1 is fixed to the motor mounting bracket 25 of the lower traveling body by fixing bolts (not shown) inserted into the bolt mounting holes 22B. Things.

Here, a motor mounting hole 25A having an outer diameter Da is formed in the mounting bracket 25 as shown by an imaginary line in FIG. 2, and a motor housing of the hydraulic motor 1 is provided in the motor mounting hole 25A. 21 is inserted except for the mounting flange 22A. For smooth insertion, the end cover 24 of the motor housing 21 is formed such that the outermost diameter portion 24A has an outer diameter dimension Db (Db <Da) smaller than the motor mounting hole 25A.

Reference numeral 26 denotes a traveling speed reducer attached to the traveling hydraulic motor 1. The speed reducer 26 includes a speed reducer housing 27 and a planetary gear speed reduction mechanism (see FIG. 1) provided in the speed reducer housing 27. A drive wheel 28 composed of a sprocket is fixed to the outer peripheral side of the speed reducer housing 27 using a bolt 29 or the like, as shown in FIG. Then, the speed reducer 26 reduces the rotation of the hydraulic motor 1 and transmits a large rotational torque to the drive wheels 23. The drive wheels 23 rotate a crawler belt (not shown) of the lower traveling body, thereby rotating the vehicle. A traveling operation of moving forward or backward is performed.

Next, reference numerals 30A and 30B denote end covers 24 constituting a casing of the relief valve 9A as shown in FIG.
The oil holes 30A and 30B constitute a passage through which the pressure oil flows, and communicate with each other when the valve body 36 described later is opened. And these oil holes 30
The oil hole 30A of A and 30B forms a part of the motor-side main line 4A2 shown in FIG. 1, and the oil hole 30B forms a part of the motor-side main line 4B2.

Reference numeral 31 denotes a valve receiving hole formed in the end cover 24 so as to communicate between the oil holes 30A and 30B. The valve receiving hole 31 is formed as a stepped bottomed hole as shown in FIG. The opening end side is a screw hole 31A. The valve receiving hole 31 has a cylinder hole 31C between the screw hole 31A and the reduced diameter hole 31B on the back side, and a free piston 41 described later is slidably inserted into the cylinder hole 31C. It is fitted.

Further, the position of the valve receiving hole 31 further deeper than the reduced diameter hole 31B is a positioning hole 31D, and the positioning hole 31D is located between the oil holes 30A and 30B.
This is for positioning a valve seat cylinder 35 described later in a fitted state.

Reference numeral 32 denotes a seat surface formed on the end surface 24A side of the end cover 24 located on the opening end side of the valve housing hole 31.
The seat surface 32 is formed as a shallow circular hole as shown in FIG. 4, and its depth T is, for example, about 2 to 4 mm (mm) with respect to the end face 24 </ b> A of the end cover 24. Then, the opening end side of the valve housing hole 31 is connected to a lid 3 described later.
When closing with the use of the flange 9, a flange 39 </ b> C described below is fastened on the seat surface 32.

Reference numeral 33 denotes a valve cylinder which is inserted into the valve receiving hole 31 by using the lid 31. The valve cylinder 33 is formed as a stepped cylinder made of a high-strength metal material as shown in FIGS. It has enlarged diameter holes 33A and 33B opened at both ends in the axial direction, and a valve element sliding hole 33C located between the enlarged diameter holes 33A and 33B and formed to have a smaller diameter. I have. In the valve cylinder 33, radial holes 33D, 33D,
Are formed, and each radial hole 33D is always in communication with the oil hole 30B.

The valve barrel 33 is fixed at its base end into a fitting hole 39F of the lid 39, which will be described later, by means such as press fitting. Has been inserted. A small-diameter throttle hole 33E is formed in the valve cylinder 33 at the base end of the enlarged-diameter hole 33A.
E is a part that allows the spring chamber 34 in the enlarged diameter hole 33A to always communicate with an oil chamber 42 described later.

Here, the spring chamber 34 is located in the enlarged diameter hole 33A of the valve cylinder 33, and the fitting hole 39F of the lid 39 and the valve 36
And a spring receiver 37 described later in the spring chamber 34.
And a valve spring 38 are provided.

Reference numeral 35 denotes a positioning hole 31D of the valve receiving hole 31.
A valve seat cylinder as a valve seat member removably fitted and fixed inside the valve seat cylinder, the valve seat cylinder 35 is formed as a stepped cylindrical body from a high-strength metal material, and is inserted into the valve housing hole 31. At the time of assembling, the fitting is made in advance to the front end side of the enlarged diameter hole portion 33B of the valve cylinder 33 to be integrated with the valve cylinder 33. And, the valve seat cylinder 35
Is inserted into the back side of the valve housing hole 31 in this state, and is fixed in the positioning hole 31D. The valve seat cylinder 35 has an annular valve seat 35A on the side facing the valve body 36.

Numeral 36 denotes a valve element inserted into the valve element sliding hole 33 of the valve element 33. The valve element 36 is provided together with the valve seat element 35 in the valve element 33.
And in this state, the cover 39
It can be attached to And the valve element 36 is a valve seat 3
By detaching and seating at 5A, the oil holes 30A and 30B are communicated and shut off via the radial holes 33D and the like of the valve seat cylinder 35 and the valve cylinder 33.

An orifice hole 36A is formed in the valve body 36 as a throttle passage extending in the axial direction. The orifice hole 36A always connects the inside of the spring chamber 34 to the valve seat cylinder 35 side. When a brake pressure or the like acts on the valve element 36 from the oil hole 30A via the valve seat cylinder 35, this pressure is guided into the spring chamber 34 through the orifice hole 36A.

Reference numeral 37 denotes a spring receiver disposed together with a valve spring 38 in the spring chamber 34. The spring receiver 37 is formed as a short stepped cylindrical body, and is provided to be fitted to an end of the valve body 36. ing. Further, the valve spring 38 is connected to the valve body 36 via a spring receiver 37.
Is normally urged in the valve closing direction, and the valve opening pressure (relief set pressure) of the valve element 36 is set to, for example, the pressure P2 shown in FIG.

Reference numeral 39 denotes a threaded lid which is a component of the relief valve 9A.
At the same time, the opening end side of the valve housing hole 31 is closed, and together with the valve cylinder 33, the valve seat cylinder 35 and the valve element 36, a cartridge type relief valve is constituted. The lid 39 is formed as a short plug with a flange made of a high-strength metal material.

That is, the lid 39 is provided with the valve accommodation hole 31 on the outer peripheral side.
And a body 39B formed with a male screw 39A to be screwed into the screw hole 31A, and formed on one side in the axial direction of the body 39B to have a larger diameter than the body 39B, and the outer peripheral side is a seating surface. And a substantially disk-shaped head 39D serving as an annular flange portion 39C fastened on the upper surface 32 of the valve cylinder 3
3. It has the largest outer diameter among the components such as the valve seat cylinder 35 and the lid 39.

The lid 39 has an engagement recess 39E formed of a hexagonal hole with a bottom located at the center of the head 39D. 3
It is recessed toward the 9B side. Then, the engagement recess 39
A tool (not shown) such as a hexagon wrench is engaged with E, and a rotational torque is applied to the lid 39 by using this tool.
The screw holes 31A are screwed with an appropriate tightening torque.

A bottomed fitting hole 39F is formed in the body 39B of the lid 39 on the other side in the axial direction and radially inward of the male screw 39A and serves as a fitting portion. The hole 39F faces the engaging recess 39E in the axial direction. Then, the valve cylinder 33 is fitted and mounted in the fitting hole 39F, whereby the valve cylinder 33 is preliminarily assembled to the lid 39, and is unitized as shown in FIG.

Here, as shown in FIG. 4, the lid 39 has an axial height H of the head 39D and an effective diameter D of the male screw 39A.
When the unit is millimeters (mm) with respect to the depth T of the seat surface 32, the relationship is set to satisfy the following expression.

[0061]

## EQU1 ## H <(0.3 × D) + T + 5

Thus, the lid 39 has a dimension (HT) in which the head 39D protrudes from the end face 24A of the end cover 24.
Can be reduced, and the lid 39 can be accommodated within the range of the outer diameter Db shown in FIGS. 2 and 3, that is, inside the outermost diameter portion 24A of the end cover 24.

Generally, the head of the hexagonal bolt or the like has a height (0.3 × D + 5) with respect to the effective diameter D of the male thread.
Designed on the basis of the following values, for example, in order to apply a sufficient tightening torque to a hexagon bolt using a tool such as a wrench, the minimum required head height is (0.3 × D +
5) It is indicated by the following value.

As shown in FIG. 4, the lid 39 fits from the end face of the head 39D to the dimension L1 from the end face of the head 39D to the end face of the body 39B (end of the male screw 39A). Reduce the dimension L2 to the end face of the mating hole 39F (L2 <L
1) The entire length of the relief valve 9A is shortened by storing a part of the valve cylinder 33 in the fitting hole 39F.

Reference numeral 40 denotes a cover 39 for opening the valve housing hole 31 to the open end.
With an O-ring as a sealing member that closes liquid tightly,
The O-ring 40 is composed of a screw 39 A of the cover 39 and a flange 39.
C, and is mounted on the outer peripheral side of the body 39B, and the oil liquid in the valve housing hole 31 is flushed with the flange 39C of the lid 39 and the seat surface 32.
To prevent leakage from outside.

Reference numeral 41 denotes a cylinder hole 31C of the valve receiving hole 31.
And a free piston 41 slidably fitted on the outer peripheral side of the valve cylinder 33, and the free piston 41 divides the annular space between the cylinder hole 31C and the valve cylinder 33 into two oil chambers 4.
2,43. And the free piston 41
Is the accumulator 10 shown in FIG.
A (10B).

That is, when pressure oil is supplied from the spring chamber 34 through the throttle hole 33E into the oil chamber 42 serving as the oil storage chamber of the accumulator 10A, the free piston 41 causes the oil chamber 43 The sliding displacement is performed toward the side, and the substantial valve opening time of the valve body 36 is delayed until the time t1 illustrated in FIG.

The relief valves 9A and 9B according to the present embodiment
The traveling hydraulic circuit of the hydraulic shovel having the above configuration has the above-described configuration. Next, the operation thereof will be described.

First, when the operator switches the direction switching valve 5 from the neutral position (a) to the switching position (b) or (c) in order to run the vehicle, the pressure control valve 8 of the counter balance valve 6 is interlocked therewith. Then, the position is switched from the neutral position (a) to the switching position (b) or (c). As a result, the traveling hydraulic motor 1 is supplied and discharged with pressure oil from the hydraulic pump 2, and is driven to rotate in the direction of arrow A or the direction of arrow B in FIG.

The rotation of the hydraulic motor 1 is
, The rotation output of the large torque is transmitted to the drive wheels 23, and the drive wheels 23 rotate the crawler belt of the lower traveling body, so that the vehicle moves forward or backward.

In order to stop the rotation of the hydraulic motor 1, for example, a case where the direction switching valve 5 is returned from the switching position (C) to the neutral position (A) will be described. By returning to the neutral position (a), the pressure difference between the hydraulic power source side main lines 4A1 and 4B1 is reduced, so that the pressure control valve 8 of the counter balance valve 6 returns to the neutral position (a), and the hydraulic motor 1 The pressurized oil is sealed in the motor-side main pipelines 4A2 and 4B2 with the counterbalance valve 6.

When the hydraulic motor 1 rotates by inertia due to the inertial load from the vehicle at this time, the hydraulic motor 1 performs a pumping operation and removes the pressure oil sucked from the motor-side main line 4B2 to the motor-side main line 4A2. By discharging to
A high-pressure brake pressure is generated on the motor side main line 4A2, and a hydraulic brake is applied to the hydraulic motor 1.

The brake pressure in the motor-side main line 4A2 acts on the valve element 36 via the oil hole 30A and the valve seat cylinder 35 shown in FIGS. It is guided to the spring chamber 34 side through the throttle hole 36A. Then, the pressure in the spring chamber 34 is supplied to the oil chamber 42 as an oil storage chamber of the accumulator 10A through the throttle hole 33E of the valve cylinder 33, so that the free piston 41 is moved to the oil chamber 42.
From the side to the oil chamber 43 side.

As a result, the pressure in the spring chamber 34 temporarily decreases, and a pressure difference is generated between the pressure in the valve seat cylinder 35 and the pressure in the spring chamber 34. A low-pressure relief operation is performed to slightly open the valve against the spring 38, and the brake pressure on the motor-side main pipeline 4A2 (oil hole 30A) side is suppressed from increasing to, for example, a pressure P1 or more shown in FIG.

When the free piston 41 slides to the position of the reduced diameter portion 31B of the valve receiving hole 31 at the time t1, the pressure in the spring chamber 34 is thereby changed according to the pressure on the valve seat cylinder 35 side. The pressure is gradually increased, and the valve element 36 maintains the valve closed state again. For this reason, the brake pressure on the oil hole 30A side increases again. For example, when the valve body 36 opens against the valve spring 38 at the pressure P2 shown in FIG. 7, the brake pressure increases more than this. Can be suppressed.

As a result, the brake pressure due to the inertial rotation of the hydraulic motor 1 can be controlled in two stages as shown by the characteristic line in FIG. 7, and the shock generated when the valve body 36 is opened can be reduced to provide a shockless function. When the valve body 36 is opened, the inertia energy of the hydraulic motor 1 is absorbed by the resistance of the pressure oil (brake pressure) flowing between the valve seat 35A and the valve body 36 when the valve body 36 is opened, and the rotation of the hydraulic motor 1 is stopped. Can be stopped gradually.

In this embodiment, the relief valve 9A (9B) is connected to the valve cylinder 33 and the valve seat cylinder 3 as shown in FIG.
5. The cartridge 36 is configured as a cartridge type relief valve by the valve body 36 and the lid 39, and the fitting hole 39F of the lid 39 is formed.
The base end side of the valve cylinder 33 is fitted therein, and the valve seat cylinder 35 and the valve element 36 are previously assembled to the distal end side of the valve cylinder 33.

Thus, the valve cylinder 33 and the valve seat cylinder 3
5, the pre-assembly including the valve body 36 and the lid 39 can be handled as a single unit body as shown in FIG. 5, and the disassembling and assembling work of the unit body with respect to the valve housing hole 31 can be efficiently performed. It can be carried out.

The cover 39 has a screw 39 on the outer peripheral side.
A body portion 39B having an A. The body portion 39B is formed on the upper end side of the body portion 39B and has a larger diameter than the body portion 39B.
2, a substantially disk-shaped head 39D serving as an annular flange 39C fastened on the upper part, and an engagement recess 39E formed of a hexagonal hole with a bottom formed at the center of the head 39D. Thus, a short flanged plug is configured.

For this reason, when the cover 39 is screwed into the opening end side of the valve housing hole 31 as shown in FIG. 6, a tool such as a hexagon wrench is engaged with the engaging recess 39E of the cover 39,
By applying a rotational torque to the lid 39 using this tool, the external thread 39A of the lid 39 can be screwed into the screw hole 31A of the valve receiving hole 31 with an appropriate tightening torque.

The head 39D of the lid 39 is expressed by the above equation (1).
Since the dimension (HT) in which the head 39D projects from the end surface 24A of the end cover 24 is small, the lid 39 is shown in FIGS. 2 and 3. The outer diameter Db can be accommodated inside the outermost diameter portion 24A of the end cover 24, so that the mounting operation of the motor housing 21 of the hydraulic motor 1 to the motor mounting bracket 25 on the lower traveling body side can be smoothly performed. It can be carried out.

Further, the head 39D of the lid body 39 is
Since the dimension (HT) protruding outside from the opening end side of the hydraulic motor 1 can be reduced, the entire motor housing 21 of the hydraulic motor 1 can be reduced in size and weight. And the head 39
By reducing the axial height H of D, the axial dimension of the lid 39 itself can be shortened, and the lid 39, the valve cylinder 3
3. The total length of the relief valves 9A and 9B composed of components such as the valve seat cylinder 35 and the valve element 36 can be shortened.
A and 9B can be reduced in size and weight.

Further, the body portion 39B of the lid 39 has a male screw 3
9A, a fitting hole 39F is provided on the radial inside of the fitting hole 39F.
F, the base end side of the valve cylinder 33 is fitted into the fitting hole 3.
Since the valve spring 38 is configured to abut on the end face of the 9F, the radially inner portion of the external thread 39A can be effectively used as the fitting hole 39F.
The overall length of 9B can be shortened, and the size and weight can be reduced.

Further, the outer peripheral surface of the valve cylinder 33 extending in the axial direction from the fitting hole 39F of the lid 39 can be effectively used as a sliding surface of the free piston 41, thereby also allowing the relief valves 9A and 9B to be downsized. Can be planned.

Therefore, according to the present embodiment, the cartridge type relief valves 9A and 9B can be formed compactly, the overall length can be shortened, the size and weight can be reduced, and the workability during disassembly and assembly can be achieved. Can be improved.

In particular, during maintenance of the relief valves 9A and 9B, the cover 39 is rotated from the outside of the end cover 24, and the male screw 39A is screwed into the screw hole 31A of the valve housing hole 31.
By simply removing the cover 39 from the valve housing 33, the valve cylinder 33 and the valve seat cylinder 35 can be easily extracted from the valve housing hole 31, and the disassembling operation and the like can be performed efficiently.

Next, FIG. 8 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Shall be. However, a feature of the present embodiment is that the valve housing hole 51 formed in the end cover 24 serving as the casing of the relief valve 9A is configured by the screw hole 51A, the reduced diameter hole 51B, and the positioning hole 51C. is there.

Here, the valve receiving hole 51 is different in that the valve receiving hole 31 and the cylinder hole 31C described in the first embodiment are eliminated, but is otherwise the same. . The valve receiving hole 51 is configured such that the reduced diameter hole portion 51B extends relatively long in the axial direction.

Also, the valve cylinder 5 inserted into the valve accommodation hole 51
2 is the valve cylinder 33 and the throttle hole 33 described in the first embodiment.
E, except that the diameter-expanding holes 52A, 52
B, a valve body sliding hole 52C and radial holes 52D, 52D.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those of the first embodiment can be obtained. However, in the present embodiment, in particular, in the first embodiment, Since the free piston 41 and the like shown in FIG. 4 are eliminated as compared with the above, the overall configuration is simplified, and a cartridge type relief valve can be manufactured at lower cost.

Next, FIG. 9 shows a third embodiment of the present invention. In this embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Shall be. However, a feature of the present embodiment is that the lid 62 that closes the opening end side of the valve receiving hole 61 includes a body 62B having a male screw 62A, a head 62D having a flange 62C, and a head 62D having a flange 62C. And a fitting projection 62F protruding downward from the lower surface of the body 62B.

Here, similarly to the valve receiving hole 51 described in the second embodiment, the valve receiving hole 61 is formed in the end cover 24 serving as a casing of the relief valve 9A, and has a screw hole on the opening end side. It comprises a portion 61A, a reduced diameter hole 61B, a positioning hole 61C on the back side, and the like.

The lid 62 has substantially the same structure as the lid 39 described in the first embodiment, but the lid 62 has a fitting portion formed as a fitting projection 62F. Are different. The base end of the valve cylinder 63 is fitted and attached to the outer peripheral side of the fitting projection 62F.

The valve cylinder 63 has substantially the same construction as the valve cylinder 33 described in the first embodiment except for the throttle hole 33E, and includes enlarged diameter portions 63A and 63B, a valve body sliding hole 63C and a diameter. It has direction holes 63D, 63D. As a result, the valve cylinder 63, the valve seat cylinder 35, the valve element 36, and the like are pre-assembled on the lid 62.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those in the first embodiment can be obtained. In the present embodiment, the first
The free piston 41 shown in FIG.
Since these are eliminated, the overall configuration can be simplified and a cartridge type relief valve can be manufactured at lower cost.

Next, FIG. 10 shows a fourth embodiment of the present invention. In the present embodiment, the same reference numerals are given to the same components as those in the above-described second embodiment, and description thereof will be given. It shall be omitted. However, the feature of this embodiment is that the valve cylinder 7
1, a valve seat cylinder 72 is integrally formed on the distal end side of the valve seat cylinder 72.
The structure is such that the valve body 73 is separated from and seated on the valve seat 72A.

Here, the valve cylinder 71 is provided with the enlarged diameter holes 71A and 71A in substantially the same manner as the valve cylinder 52 described in the second embodiment.
B, a valve body sliding hole 71C and radial holes 71D, 71D. However, the valve cylinder 71 is formed integrally with a valve seat cylinder 72 at the distal end side of the enlarged-diameter hole 71B, and the valve seat cylinder 72 is a valve seat 72A having a tapered shape on the surface facing the valve body 73. ing.

The valve body 73 is provided in the valve body sliding hole 7 of the valve cylinder 71.
By inserting and fitting into the valve seat 1C and taking off and seating on the valve seat 72A, the oil holes 30A and 30B are communicated and blocked almost in the same manner as the valve body 36 described in the first embodiment. An orifice hole 73A is formed in the valve body 73 as a throttle passage extending in the axial direction. The orifice hole 73A is always in communication with the inside of the spring chamber 34.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effects as those of the second embodiment can be obtained.
By integrally forming the valve seat cylinder 72 in the first embodiment, the workability during assembly can be further simplified.

In each of the above embodiments, the cover 39
Although the engagement recess 39E (62E) of (62) has been described as being formed as a hexagonal hole with a bottom, the present invention is not limited to this. For example, the engagement recess may have a square, pentagon, or star shape. The engagement recess may be a non-circular recess so that the cover can be rotated using a tool such as a wrench.

In each of the above embodiments, the case where the traveling hydraulic motor 1 is used for the relief valves 9A and 9B has been described as an example. However, the present invention is not limited to this. The present invention can also be applied to a relief motor using a hydraulic motor for rope winches or the like or other uses. The present invention is not limited to a hydraulic shovel, a hydraulic crane, and the like, but can be widely applied to a relief valve of another construction machine.

[0102]

As described in detail above, according to the first aspect of the present invention, the lid used for the cartridge type relief valve is provided with a body having a thread formed on the outer peripheral side, A substantially disk-shaped head which is located on one side in the axial direction, has a larger diameter than the body, and has an annular flange portion whose outer peripheral side is fastened to a seating surface on the casing side; A non-circular engagement concave portion recessed from the end face toward the body portion side, and a fitting portion provided on the other side in the axial direction of the body portion and fitted with and fitted with a valve cylinder are provided. Therefore, in a state where the valve body is fitted to the fitting portion of the lid body, the valve body and the valve body can be pre-assembled to the lid body to form a unit, and this unit body is accommodated in the casing by the valve housing. By inserting the lid into the hole and screwing the lid to the opening end side, the assembling work of the relief valve can be easily performed.

[0103] A rotating torque for tightening can be applied to the head of the lid by engaging a tool such as a wrench in the engaging recess, and the protrusion of the casing from the seat surface has a disc-shaped head. Can be kept smaller. Therefore, the overall length of the relief valve can be shortened to reduce the size and weight, and the workability during disassembly and assembly can be improved.

According to the second aspect of the present invention, an annular seal member is provided on the outer peripheral side of the body of the lid between the flange and the male screw, and the seal member is provided in the opening of the valve accommodating hole. Since the end side is sealed together with the flange, the valve housing hole provided in the casing can be sealed in a liquid-tight manner with a sealing member to the outside, and the pressure oil in the casing is reliably prevented from leaking to the outside. can do.

According to the third aspect of the present invention, the bottomed fitting is formed in the body portion with the fitting portion of the lid positioned radially inside the male screw and opposed to the engaging concave portion in the axial direction. It is a mating hole, and it is configured to be pre-assembled to the lid by fitting the valve cylinder into the fitting hole, so that a part of the valve cylinder can be accommodated in the fitting hole of the lid, and thereby the relief valve The total length can be further reduced, and the size and weight can be reduced.

On the other hand, in the invention according to claim 4, the fitting portion of the lid is a fitting projection protruding in the axial direction from the other end face in the axial direction of the body, and the valve cylinder is formed of the fitting projection. Since it is configured to be pre-assembled to the lid by fitting to the outer peripheral side, the valve body and the valve cylinder are attached to the lid in a state where the valve cylinder is fitted to the fitting convex outer peripheral side of the lid. On the other hand, it can be pre-assembled and unitized, and the cartridge type relief valve can be easily assembled to the casing.

According to the fifth aspect of the present invention, the height H in the axial direction of the head can be reduced, the dimension (HT) in which the head projects from the end face of the casing can be reliably reduced, and the entire relief valve can be reduced. Can be reduced in size.

According to the invention described in claim 6, the valve cylinder is formed of a stepped cylindrical body in which one end side is fitted to the lid and a portion in the length direction is a valve body sliding hole. Since a spring chamber accommodating a valve spring for constantly biasing the valve element in the valve closing direction is formed in the cylinder between the lid and the lid, the valve spring is disposed in the valve cylinder. In this state, the valve body is assembled to the valve body, and in this state, the valve body is assembled to the lid, so that they can be handled as a single unit, and the cartridge type relief valve can be easily assembled to the casing. Can be attached or removed.

According to the seventh aspect of the present invention, a valve seat member is provided at the other end side of the valve cylinder and located on the back side of the valve accommodating hole, on which the valve element is detachably seated. Is pre-assembled to the lid via the valve cylinder, so the valve seat member and the valve can be pre-assembled to the lid via the valve cylinder, and these can be easily unitized. In addition, the cartridge type relief valve can be efficiently disassembled and assembled.

Further, according to the invention of claim 8,
The casing is composed of a motor housing of a traveling hydraulic motor used for construction equipment, and the head of the lid is configured to be housed inside the outermost diameter portion of the motor housing.
The head of the lid does not protrude outward in the radial direction of the motor housing. For example, the work of attaching the motor housing to the frame of the lower traveling body can be easily performed.
The outer diameter of the motor housing can be reduced, and the traveling hydraulic motor can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a traveling hydraulic circuit diagram of a hydraulic shovel to which a relief valve according to a first embodiment of the present invention is applied.

FIG. 2 is a partially broken external view showing a traveling hydraulic motor and a reduction gear provided with a relief valve.

FIG. 3 is a right side view of FIG. 2 showing a traveling hydraulic motor and a speed reducer with drive wheels removed.

FIG. 4 is a longitudinal sectional view showing the relief valve enlarged from an arrow IV-IV in FIG. 2;

FIG. 5 is an enlarged cross-sectional view showing a state in which a valve cylinder, a valve seat cylinder, and a valve body are preliminarily assembled to a lid body.

FIG. 6 is an enlarged view of a main part of the relief valve shown in FIG.

FIG. 7 is a characteristic diagram showing a relief characteristic of the relief valve according to the first embodiment.

FIG. 8 is a longitudinal sectional view showing a relief valve according to a second embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing a relief valve according to a third embodiment of the present invention.

FIG. 10 is a longitudinal sectional view showing a relief valve according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2 Hydraulic pump 4A, 4B main pipeline 5 Direction control valve 9A, 9B Relief valve 21 Motor housing 24 End cover (casing) 24A Outer diameter part 30A, 30B Oil hole (passage) 31, 51, 61 Valve accommodation hole 32 seat surface 33, 52, 63, 71 valve cylinder 33C, 52C, 63C, 71C valve body sliding hole 34 spring chamber 35, 72 valve seat cylinder (valve seat member) 35A, 72A valve seat 36, 73 valve body 38 valve Spring 39, 62 Lid 39A, 62A Male thread 39B, 62B Trunk 39C, 62C Flange 39D, 62D Head 39E, 62E Engaging recess 39F Fitting hole (fitting part) 40 O-ring (seal member) 41 Free Piston 62F fitting projection (fitting part)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Takashi Shindome Inventor F-term (reference) 3H059 AA06 BB22 BB30 CC11 CD05 CF01 DD17 EE01 EE13 FF03 FF16 3H060, Tsuchiura Plant, Tsuchiura-shi, Ibaraki Pref. AA02 BB08 BB10 CC22 CC29 DC05 DD05 DD14 DE01 EE08 FF03 FF06 HH04 HH19 3H089 AA61 BB27 CC08 DA02 DB04 DB08 DB46 DB49 DB55 DB73 DB76 DB78 DB79 GG02 JJ02

Claims (8)

[Claims] 1. A casing having a passage through which pressurized oil flows and having a valve receiving hole formed in the passage, an excess pressure generated in the passage inserted into the valve receiving hole of the casing from an opening end side. A valve body provided with a valve body which is detachably seated on a valve seat to relieve the pressure, and the valve body is screwed to the opening end side of the valve accommodating hole from the outside of the casing in a state where the valve body is previously assembled. A relief valve comprising a threaded lid for closing the valve receiving hole, wherein the lid has a body formed with a male screw screwed to an opening end side of the valve receiving hole on an outer peripheral side; A substantially disk-shaped head which is located on one side in the axial direction of the body portion and has a larger diameter than the body portion and has an annular flange portion whose outer peripheral side is fastened to the seating surface on the casing side; A tool that is recessed from the end face of the head toward the body to apply a rotational torque to the male screw; A relief valve characterized by comprising a non-circular engagement concave portion that can be fitted, and a fitting portion provided on the other axial side of the body portion and fitted with and attached to the valve cylinder. . 2. An annular seal member is provided between the flange portion and the male screw on the outer peripheral side of the trunk portion of the lid, and the seal member is configured such that an opening end side of the valve housing hole is formed in the flange portion. The relief valve according to claim 1, wherein the relief valve is configured to seal with the relief valve. 3. The fitting portion of the lid includes a bottomed fitting hole that is formed on the body portion and located inward of the male screw in the radial direction and that faces the engaging recess in the axial direction. 3. The relief valve according to claim 1, wherein the valve cylinder has a configuration in which one end side is fitted into the fitting hole and preliminarily assembled to the lid. 4. 4. The fitting portion of the lid body includes a fitting protrusion protruding in the axial direction from the other end surface in the axial direction of the body portion, and one end of the valve cylinder is provided on an outer peripheral side of the fitting protrusion. The relief valve according to claim 1, wherein the relief valve is configured to be fitted and preliminarily assembled to the lid. 5. The height H in the axial direction of the head is expressed by the following formula: when the unit is millimeters (mm) with respect to the effective diameter D of the male screw and the seating depth T of the casing. The relief valve according to claim 1, wherein the relationship is set as follows: 0.3 × D) + T + 5. 6. The valve body comprises a stepped cylindrical body having one end fitted to the lid and having a valve body sliding hole at an intermediate position in a longitudinal direction, and the valve body is provided in the valve body. 6. The relief valve according to claim 1, wherein a spring chamber accommodating a valve spring biased in a normally closed direction is formed between the valve body and the lid. 7. A valve seat member having a valve seat at the other end side of the valve cylinder, the valve seat being located at a depth side of the valve receiving hole and on which the valve element is detached and seated, wherein the valve seat member is provided with 6. A structure in which the lid is pre-assembled via a valve sleeve.
Or the relief valve according to 6. 8. The motor according to claim 1, wherein the casing is formed of a motor housing of a traveling hydraulic motor used for a construction machine, and a head of the lid is housed inside an outermost diameter portion of the motor housing. , 3, 4, 5, 6 or 7.